Various quotes from Church leaders on the Constitution hanging by a thread.  References to the source are included.  There are a myriad of other quotes.  I have stuck to ones which come from Church publications or other similar reliable sources.

The Prophecy of Joseph Smith on the United States And the Constitution Hanging by a Thread

Prophecy of Joseph Smith (March 10, 1844):

Even this nation will be on the verge of crumbling to pieces and tumbling to the ground and when the Constitution is on the brink of ruin this people will be the staff upon which the nation shall lean and they shall bear the Constitution away from the very verge of destruction. (Source: Joseph Smith Papers, LDS Church Historical Archives, Box 1, March 10, 1844; D. Michael Stewart, Ensign, Vol. 6, No. 6, June 1976, pp. 64-65)

Revelation to Joseph Smith (1831):

Verily, Verily, saith the Lord, your Redeemer, even Jesus Christ . . . Verily, I say unto you, that the day of vexation and vengeance is nigh at the doors of this nation, when wicked, ungodly, and daring men will rise up in wrath and might, and go forth in anger, like as the dust is driven by a terrible wind; and they will be the means of the destruction of the government and cause the death and misery of many souls; but the faithful among my people shall be preserved in holy places during all these tribulations. (Source: Revelation given to Joseph Smith, July 17, 1831, west of Jackson County, Missouri, contained in a letter from W. W. Phelps to Brigham Young, dated August 12, 1861, Joseph Smith Collection, Church Historian's Office.)

Prophecy of Joseph Smith (1833):

And now I am prepared to say by the authority of Jesus Christ, that not many years shall pass away before the United States shall present such a scene of bloodshed as has not a parallel in the history of our nation; pestilence, hail, famine, and earthquake will sweep the wicked of this generation from off the face of the land, to open and prepare the way for the return of the lost tribes of Israel from the north country. (Source: Documentary History of the Church, Vol.1, p. 315-316, January 4, 1833)

Prophecy of Joseph Smith (February 6, 1840):

I arrived safely at Nauvoo, after a wearisome journey (to Washington D.C.), through alternate snow and mud, having witnessed many vexatious movements in government officers, whose sole object should be the peace and prosperity and happiness of the whole people; but instead of this, I discovered that popular clamor and personal aggrandizement were the ruling principles of those in authority; and my heart faints within me when I see, by the visions of the Almighty, the end of this nation, if she continues to disregard the cries and petitions of her virtuous citizens, as she has done, and is now doing. (Source: Documentary History of the Church, Vol. 4, p. 89)

Prophecy of Joseph Smith (May 18, 1843):

I prophesy in the name of the Lord God of Israel, unless the United States redress the wrongs committed upon the Saints in the state of Missouri and punish the crimes committed by her officers that in a few years the government will be utterly overthrown and wasted, and there will not be so much as a potsherd left. (Source: Documentary History of the Church, Vol. 5, p. 394)

Prophecy of Joseph Smith (December 16, 1843):

While discussing the petition to Congress, I prophesied by virtue of the holy Priesthood vested in me, and in the name of the Lord Jesus Christ, that if Congress will not hear our petition and grant us protection, they shall be broken up as a government. (Source: Documentary History of the Church, Vol 6. p. 116)

Prophecy of Joseph Smith:

They shall have mobbing to their hearts content, if they do not redress the wrongs of the Latter-day Saints. Mobs will not decrease, but will increase until the whole government becomes a mob, and eventually it will be State against State, city against city, neighborhood against neighborhood. (Source: As quoted by Brigham Young in Deseret News, Vol II. No. 9, May 1, 1861)

Prophecy of Joseph Smith, as recorded by Parley P. Pratt (January 21, 1841):

The government is fallen and needs redeeming. It is guilty of blood and cannot stand as it is now is, but will come so near desolation as to hang as it were by a single hair! Then the servants go to the nations of the earth, and gather the strength of the Lord's house! A mighty army! And this is the redemption of Zion when the saints shall have redeemed that government and reinstated it in all its purity and glory![D&C 101:43] (Source: George A. Smith Papers, Church Archives, Box 7, Folder 5; D. Michael Stewart, Ensign, vol. 6, No. 6, Jun 1976, pp. 64-65)

Prophecy of Joseph Smith, according to Brigham Young:

The time will come when the destiny of the nation will hang upon a single thread. At that critical juncture, this people will step forth and save it from the threatened destruction. (Source: Journal of Discourses, Vol. 7, p. 15, July 4, 1854)

Prophecy of Joseph Smith, according to Orson Hyde:

The time would come when the Constitution and the country would be in danger of an overthrow; and . . . if the Constitution be saved at all, it will be by the Elders of this Church. (Source: Journal of Discourses, Vol.6, p. 152, January 3, 1858)

D&C 101:10-12;43-62;76-91 (received by Joseph Smith):

I have sworn, and the decree hath gone forth by a former commandment which I have given unto you, that I would let fall the sword of mine indignation in behalf of my people; and even as I have said, it shall come to pass. Mine indignation is soon to be poured out without measure upon all nations; and this will I do when the cup of their iniquity is full. And in that day all who are found upon the watch-tower, or in other words, all mine Israel, shall be saved . . .

And now, I will show unto you a parable, that you may know my will concerning the redemption of Zion. A certain nobleman had a spot of land, very choice; and he said unto his servants: Go ye unto my vineyard, even upon this very choice piece of land, and plant twelve olive-trees; And set watchmen round about them, and build a tower, that one may overlook the land round about, to be a watchman upon the tower, that mine olive-trees may not be broken down when the enemy shall come to spoil and take upon themselves the fruit of my vineyard. Now, the servants of the nobleman went and did as their lord commanded them, and planted the olive-trees, and built a hedge round about, and set watchmen, and began to build a tower. And while they were yet laying the foundation thereof, they began to say among themselves: And what need hath my lord of this tower? And consulted for a long time, saying among themselves: What need hath my lord of this tower, seeing this is a time of peace? Might not this money be given to the exchangers? For there is no need of these things. And while they were at variance one with another they became very slothful, and they hearkened not unto the commandments of their lord. And the enemy came by night, and broke down the hedge; and the servants of the nobleman arose and were affrighted, and fled; and the enemy destroyed their works, and broke down the olive-trees. Now, behold, the nobleman, the lord of the vineyard, called upon his servants, and said unto them, Why! what is the cause of this great evil? Ought ye not to have done even as I commanded you, and- after ye had planted the vineyard, and built the hedge round about, and set watchmen upon the walls thereof- built the tower also, and set a watchman upon the tower, and watched for my vineyard, and not have fallen asleep, lest the enemy should come upon you? And behold, the watchman upon the tower would have seen the enemy while he was yet afar off; and then ye could have made ready and kept the enemy from breaking down the hedge thereof, and saved my vineyard from the hands of the destroyer. And the lord of the vineyard said unto one of his servants: Go and gather together the residue of my servants, and take all the strength of mine house, which are my warriors, my young men, and they that are of middle age also among all my servants, who are the strength of mine house, save those only whom I have appointed to tarry; And go ye straightway unto the land of my vineyard, and redeem my vineyard; for it is mine; I have bought it with money. Therefore, get ye straightway unto my land; break down the walls of mine enemies; throw down their tower, and scatter their watchmen. And inasmuch as they gather together against you, avenge me of mine enemies, that by and by I may come with the residue of mine house and possess the land. And the servant said unto his lord: When shall these things be? And he said unto his servant: When I will; go ye straightway, and do all things whatsoever I have commanded you; And this shall be my seal and blessing upon you- a faithful and wise steward in the midst of mine house, a ruler in my kingdom. And his servant went straightway, and did all things whatsoever his lord commanded him; and after many days all things were fulfilled . . .

And again I say unto you, those who have been scattered by their enemies, it is my will that they should continue to importune for redress, and redemption, by the hands of those who are placed as rulers and are in authority over you- According to the laws and constitution of the people, which I have suffered to be established, and should be maintained for the rights and protection of all flesh, according to just and holy principles; That every man may act in doctrine and principle pertaining to futurity, according to the moral agency which I have given unto him, that every man may be accountable for his own sins in the day of judgment. Therefore, it is not right that any man should be in bondage one to another. And for this purpose have I established the Constitution of this land, by the hands of wise men whom I raised up unto this very purpose, and redeemed the land by the shedding of blood.

Now, unto what shall I liken the children of Zion? I will liken them unto the parable of the woman and the unjust judge, for men ought always to pray and not to faint, which saith- There was in a city a judge which feared not God, neither regarded man. And there was a widow in that city, and she came unto him, saying: Avenge me of mine adversary. And he would not for a while, but afterward he said within himself: Though I fear not God, nor regard man, yet because this widow troubleth me I will avenge her, lest by her continual coming she weary me. Thus will I liken the children of Zion. Let them importune at the feet of the judge; And if he heed them not, let them importune at the feet of the governor; And if the governor heed them not, let them importune at the feet of the president; And if the president heed them not, then will the Lord arise and come forth out of his hiding place, and in his fury vex the nation; And in his hot displeasure, and in his fierce anger, in his time, will cut off those wicked, unfaithful, and unjust stewards, and appoint them their portion among hypocrites, and unbelievers; Even in outer darkness, where there is weeping, and wailing, and gnashing of teeth.

Prophecy of Brigham Young:

The nations will consume each other, and the Lord will suffer them to bring it about. It does not require much talent or tact to get up opposition these days. You see it rife in communities, in meetings, in neighborhoods, and in cities. That is the knife that will cut down this Government. The axe is laid at the root of the tree, and every tree that bringeth not forth good fruit will be hewn down. (Source: Journal of Discourses, 8:143)

Prophecy of John Taylor (General Conference, 1879):

Were we surprised when the last terrible war (the Civil War) took place here in the United States? No . . . You will see worse things than that, for God will lay his hand upon this nation and they will feel it more terribly than ever they have done before. There will be more bloodshed, more ruin, more devastation than ever they have seen before. Write it down! You will see it come to pass; it is only just starting in . . . There is yet to come a sound of war, trouble and distress, in which brother will be arrayed against brother, father against son, son against father, a scene of desolation and destruction that will permeate our land until it will be a vexation to hear the report thereof. (Source: Journal of Discourses, 20:318)

Another Prophecy of John Taylor (1879):

We have got this kingdom to build up; and it is not a phantom, but a reality. We have to do it, God expects it at our hands . . . We have got to go on and progress in these things. We have got to establish a government upon the principle of righteousness, justice, truth and equality and not according to the many false notions that exist among men. And then the day is not far distant when this nation will be shaken from centre to circumference. And now, you may write it down, any of you, and I will prophesy it in the name of God. And then will be fulfilled the prediction to be found in one of the revelations given through the prophet Joseph Smith. Those who will not take up their sword to fight against their neighbor must needs flee to Zion for safety. And they will come, saying, we do not know anything of the principles of your religion, but we perceive that you are an honest community; you administer justice and righteousness, and we want to live with you and receive the protection of your laws, but as for your religion we will talk about that some other time. Will we protect such people? Yes, all honorable men. When the people shall have torn to shreds the Constitution of the United States the Elders of Israel will be found holding it up to the nations of earth and proclaiming liberty and equal rights to all men, and extending the hand of fellowship to the oppressed of all nations. This is part of the programme, and as long as we do what is right and fear God, he will help us and stand by us under all circumstances. (Source: Journal of Discourses, 21:8)

Prophecy of Wilford Woodruff:

The Congress of 1862, and the Supreme Judges of 1879, in their acts and decisions, have taken a dangerous and fearful step; their acts will sap the very foundation of our government, and it will rent asunder, and the God of heaven will hold them responsible for these things, for 'what men sow they will reap, and the measure they mete unto others will be meted unto them', saith the Lord. The Constitution once broken by the rulers of the land, there will be no stopping place until the nation is broken in pieces, and no power beneath the heavens can save this nation from the consequences thereof. (Source: Millennial Star, 41:243)

Another Prophecy of Wilford Woodruff (1880):

The Lord . . . poured out His spirit upon me and opened the vision of my mind so that I could comprehend in a great measure the mind and will of God concerning the nation and concerning the inhabitants of Zion. I saw the wickedness of the nation, its abominations and corruptions and the judgments of God and the destruction that awaited it . . . On January 18th I was again given in a vision. It concerned the destiny of our nation and of Zion. My pillow was again wet by a fountain of tears as I beheld the judgments of God upon the wicked. I was strongly impressed that the Apostles and elders should warn the inhabitants of the earth. (Source: Matthias F. Cowley, Wilford Woodruff, p. 393. SLC, Deseret News, 1916)

Prophecy of Moses Thatcher (an early apostle):

I have seen the end of this nation and it is terrible . . . I will tell you in the name of the Lord that a secret band will sap the life of this nation. (Source: Franklin Ward Historical Record, Franklin, Idaho. June 16, 1882)

Statement of Erastus Snow:

We were told by the prophet Joseph Smith, that the United States Government and people would undermine one principle of the Constitution after another, until its whole fabric would be torn away, and that it would become the duty of the Latter-day Saints and those in sympathy with them to rescue it from destruction, and to maintain and sustain the principles of human freedom for which our fathers fought and bled. We look for these things to come in quick succession. (Source: Journal of Discourses, vol. 26, p. 226, May 31, 1885)

Statement of Charles W. Nibley:

My brethren and sisters, I hope that we will go home from this Conference determined as a great body of people, to stand for law, order, righteousness, justice and peace on earth and good will among all men. I believe as the Prophet Joseph has written, that the day would come when there would be so much of disorder, of secret combinations taking the law into their own hands, tramping upon Constitutional rights and the liberties of the people, that the Constitution would hang as by a thread. Yes, but it will still hang, and there will be enough of good people, many who may not belong to our Church at all, people who have respect for law and for order, and for Constitutional rights, who will rally around with us and save the Constitution. I have never read that that thread would be cut. It will hang; the Constitution will abide and this civilization, that the Lord has caused to be built up, will stand fortified through the power of God, by putting from our hearts all that is evil, or that is wrong in the sight of God, by our living as we should live, acceptable to him. (Source: Conference Report, October 1922, p.40)

Another statement by Charles W. Nibley:

Brethren and sisters, let me say in closing that we have it of record, that the prophet Joseph Smith said the time would come when through secret organizations taking the law into their own hands, not being governed by law or by due process of law, but becoming a law unto themselves, when, by those disintegrating activities, the Constitution of the United States would be so torn and rent asunder, and life and property and peace and security would he held of so little value, that the Constitution would, as it were, hang by a thread. But he never said, so far as I have heard, that that thread would be cut. I believe, with Elder Richards, that this Constitution will be preserved, but it will be preserved very largely in consequence of what the Lord has revealed and what this people, through listening to the Lord and being obedient, will help to bring about, to stabilize and give permanency and effect to the Constitution itself. That also is our mission. That also is what we are help to bring about, to stabilize and give permanency and effect to the Constitution itself. That also is our mission. That also is what we are here for. I glory in it. I praise God with all my heart and soul that I am a member of it. (Source: Conference Report, October 1923, p.62)

Statement of Joseph F. Smith:

As I stood upon the summit of the Hill Cumorah, in the midst of a vast multitude, only a few of whom belonged to the Church, I tried to picture the scenes of former days. Here were assembled vast armies filled with bitterness and bent on destruction. I thought of the great promises the Lord had made through his prophets concerning those who should possess this choice land, and how these promises were not fulfilled because the people violated his commandments. Here a people perished because of their extreme wickedness.

There must be something in the destiny of things that would cause a repetition of this terrible scene on the same spot many centuries later. I reflected and wondered if this unhappy time would ever come when another still mightier people would incur the wrath of God because of wickedness and likewise perish. If so, would this same spot witness their destruction? (Source: Doctrines of Salvation, Vol. III, p. 242)

Prophecy of Heber C. Kimball:

I am very thankful that so many of the brethren have come in with handcarts; my soul rejoiced, my heart was filled and grew as big as a two-bushel basket. Two companies have come through safe and sound. Is this the end of it? No; there will be millions on millions that will come much in the same way, only they will not have handcarts, for they will take their bundles under their arms, and their children on their backs, and under their arms and flee. (Source: Journal of Discourses, 4:106)

Prophecy of Brigham Young (1868):

By and by there will be a gulf between the righteous and the wicked so that they cannot trade with each other and national intercourse will cease. (Source: Journal of Discourses, 12:284)

Prophecy of Heber C. Kimball:

Lay up your stores, and take your silks and fine things, and exchange them for grain and such things as you need, and the time will come when we will be obliged to depend upon our own resources; for the time is not far distant when the curtain will be dropped between us and the United States. When that time comes, brethren and sisters, you will wish you had commenced sooner to make your own clothing. I tell you, God requires us to go into home manufacture; and prolong it as much as you like, you have got to do it. (Source: Journal of Discourses, 5:10)

Statement of Heber C. Kimball:

I will tell you a dream which Brother Kesler had lately. He dreamed that there was a sack of gold and a cat placed before him, and that he had the privilege of taking which he pleased, whereupon he took the cat, and walked off with her. Why did he take the cat in preference to the gold? Because he could eat the cat, but not eat the gold. You may see about such times before you die. (Source: Journal of Discourses, 3:262)

Statement of David Whitmer:

Question: When will the temple be built in Independence?
Answer: Right after the great tribulation is over.
Question: What do you mean by that?
Answer: A civil war more bloody and cruel than the rebellion. It will be the smashing up of this nation, about which time the second great work has to be done, a work like Joseph did, and the translation of the sealed plates and peace all over.

(Source: Interview by Dr. Poulson with David Whitmer, Deseret News, Friday, August 16, 1878)

Statement of Rex E. Lee:

A final area of constitutional interest unique to Latter-day Saints finds its source in the well-known "hanging by a thread" statements by the Prophet Joseph Smith. Similar statements have been reiterated by no fewer than six of his successors, including the current prophet . . . But in none of those quotations . . . has any Church leader ever been very specific as to the metaphor's meaning.

Unfortunately, some members of the Church have been all too ready to offer their own explanations. The only thing consistent about these explanations is that in each instance, it was the Church member's own unresolved, often very private, grievance that supplied evidence that the thread was beginning to fray, sometimes beyond repair . . .

In my view, this is another instance in which going beyond what our leaders have said can be misleading at best, and potentially fraught with mischief. Even though we have not been given the exact meaning of the prophets' statements about the Constitution hanging by a thread, the scriptures do define the conditions on which freedom in the land of America ultimately depends. I am satisfied that whatever else may eventually hang in the constitutional balance, this much is clear: The continuation of the blessings of liberty depends finally on our spiritual righteousness. As the Lord told the Jaredites in the Book of Ether, this is a "land of promise." And "whatsoever nation shall possess it shall be free from bondage, and from captivity, . . . if they will but serve the God of the land, who is Jesus Christ." If the people fail to keep this covenant, they "shall be swept off when the fullness of his wrath shall come upon them. And the fullness of his wrath cometh upon them when they are ripened in iniquity" (Ether 2:9-12). (Source: Rex E. Lee, The Constitution and the Restoration, BYU Speeches, 1991.)

Statement of Eliza R. Snow, Ogden, Utah, 1871:

I heard the prophet say, ‘The time will come when the government of these United States will be so nearly overthrown through its corruption, that the Constitution will hang as it were by a single hair, and the Latter-day Saints—the Elders of Israel—will step forward to its rescue and save it. (Journal History, MSF 143 #28, July 24, 1871; D. Michael Stewart, Ensign, June 1976.)

Statement of Jedediah M. Grant to Mormon Battalion, February 6, 1855, Salt Lake City:

What did the Prophet Joseph say? When the Constitution shall be tottering we shall be the people to save it from the hand of the foe. (Deseret News Weekly, January 19, 1870; D. Michael Stewart, Ensign, June 1976.)

Statement of Boyd K. Packer (2004):

When Moroni was translating the twenty-four gold plates, he interrupted his narrative to speak directly to us in our day. He told of the Gadiantons and their bands (in our day we would call them gangs):

Wherefore, O ye Gentiles [that is us], it is wisdom in God that these things should be shown unto you, that thereby ye may repent of your sins, and suffer not that these murderous combinations shall get above you, ...

[He then warned us in unmistakable plainness]: Wherefore, the Lord commandeth you, when ye shall see these things come among you that ye shall awake to a sense of your awful situation, because of this secret combination which shall be among you; ...

Wherefore, I, Moroni, am commanded to write these things that evil may be done away, and that the time may come that Satan may have no power upon the hearts of the children of men, but that they may be persuaded to do good continually, that they may come unto the fountain of all righteousness and be saved (Ether 8:23–24, 26).

When the Saints in Missouri were suffering great persecutions, the Lord said that the Constitution of the United States was given

that every man may act in doctrine and principle pertaining to futurity, according to the moral agency which I have given unto him. [Notice that it does not say free agency, it says moral agency. The agency we have is a moral agency.] ...

For this purpose have I established the Constitution of this land, by the hands of wise men whom I raised up unto this very purpose, and redeemed the land by the shedding of blood (D&C 101:78, 80; emphasis added).

The present major political debate centers on values and morals and the Constitution.

There occurs from time to time reference to the Constitution hanging by a thread. President Brigham Young said:

The general Constitution of our country is good, and a wholesome government could be framed upon it; for it was dictated by the invisible operations of the Almighty. ...

Will the Constitution be destroyed? No. It will be held inviolate by this people; and as Joseph Smith said "the time will come when the destiny of this nation will hang upon a single thread, and at this critical juncture, this people will step forth and save it from the threatened destruction." It will be so.23

I do not know when that day will come or how it will come to pass. I feel sure that when it does come to pass, among those who will step forward from among this people will be men who hold the Holy Priesthood and who carry as credentials a bachelor or doctor of law degree. And women, also, of honor. And there will be judges as well.

Others from the world outside the Church will come, as Colonel Thomas Kane did, and bring with them their knowledge of the law to protect this people.

We may one day stand alone, but we will not change or lower our standards or change our course.  (Source: "On the Shoulders of Giants", Brigham Young University J. Reuben Clark Law Society Devotional, Saturday, 28 February 2004, 6:00 p.m)

George Albert Smith:

I fear the time is coming . . . unless we can call the people of this world to repent of their sins and turn from the error of their ways, that the great war [World War II] that has just passed will be an insignificant thing, as far as calamity is concerned, compared to that which is before us.  (Source: Conference Report, October 9, 1946, p. 149)

George Albert Smith:  

Brethren and sisters, let us go to our homes. If our houses are not in order, let us set them in order. Let us renew our determination to honor God and keep his commandments, to love one another, to make our homes the abiding place of peace. Each of us can contribute to that in the homes in which we live. It will not be long until calamities will overtake the human family unless there is speedy repentance. It will not be long before those who are scattered over the face of the earth by millions will die like flies because of what will come.  (Source: Conference Report, April 9, 1950, p. 169)

Ezra Taft Benson:

We are fast approaching that moment prophesied by Joseph Smith when he said: 'Even this nation will be on the very verge of crumbling to pieces and tumbling to the ground, and when the Constitution is upon the brink of ruin, this people will be the staff upon which the nation shall lean, and they shall bear the Constitution away from the very verge of destruction. (The Constitution A Heavenly Banner, 1986, p.28)

Ezra Taft Benson: