James Madison quote: “The happy Union of these States is a wonder; their Constitution a miracle; their example the hope of Liberty throughout…”

“We will stand by them until the sun of liberty, fixed in the firmament of our Constitution, shall shine with equal ray upon every man, black or white, throughout the Union”

James A. Garfield (1831–1881) American politician, 20th President of the United States (in office in 1881)

1880s, Speech to the 'Boys in Blue' (1880)
Context: And it did gentle the condition and elevate the heart of every worthy soldier who fought for the Union, [applause, ] and he shall be our brother forevermore. Another thing we will remember: we will remember our allies who fought with us. Soon after the great struggle began, we looked behind the army of white rebels, and saw 4,000,000 of black people condemned to toil as slaves for our enemies; and we found that the hearts of these 4,000,000 were God-inspired with the spirit of Liberty, and that they were all our friends. [Applause. ] We have seen the white men betray the flag and fight to kill the Union; but in all that long, dreary war we never saw a traitor in a black skin. [Great cheers. ] Our comrades escaping from the starvation of prison, fleeing to our lines by the light of the North star, never feared to enter the black man's cabin and ask for bread. ["Good, good," "That's so," and loud cheers. ] In all that period of suffering and danger, no Union soldier was ever betrayed by a black man or woman. [Applause. ] And now that we have made them free, so long as we live we will stand by these black allies. [Renewed applause. ] We will stand by them until the sun of liberty, fixed in the firmament of our Constitution, shall shine with equal ray upon every man, black or white, throughout the Union. [Cheers. ] Fellow-citizens, fellow-soldiers, in this there is the beneficence of eternal justice, and by it we will stand forever. [Great applause. ] A poet has said that in individual life we rise, "On stepping-stones of our dead selves to higher things," and the Republic rises on the glorious achievements of its dead and living heroes to a higher and nobler national life. [Applause. ] We must stand guard over our past as soldiers, and over our country as the common heritage of all. [Applause. ]

“Hold on, my friends, to the Constitution and to the Republic for which it stands. Miracles do not cluster and what has happened once in 6,000 years, may not happen again. Hold on to the Constitution, for if the American Constitution should fail, there will be anarchy throughout the world.”

Daniel Webster (1782–1852) Leading American senator and statesman. January 18, 1782 – October 24, 1852. Served as the Secretary of Sta…

The earliest version of this seems to be from Savings and Loan Annual 1963, p. 56 http://books.google.com/books?id=RckuAQAAIAAJ&q=%22hold+on+my+friends+to+the+constitution%22&dq=%22hold+on+my+friends+to+the+constitution%22&hl=en&ei=yCxETrWOLMn10gHCm5TbDA&sa=X&oi=book_result&ct=result&resnum=2&ved=0CC0Q6AEwATgU published by the United States Savings and Loan League. Variants of it were quoted by President Ronald Reagan, here http://books.google.com/books?id=tfgIGkforucC&q=%22what+has+happened+once+in+6,000+years+may+never+happen+again%22&dq=%22what+has+happened+once+in+6,000+years+may+never+happen+again%22&hl=en&ei=ejxEToOHMsP20gGI8KHACQ&sa=X&oi=book_result&ct=result&resnum=1&ved=0CC0Q6AEwADgK, here http://books.google.com/books?id=BOzui4UB1xEC&q=%22American+Constitution+shall+fall%22&dq=%22American+Constitution+shall+fall%22&hl=en&ei=Fz1ETvSWAeu80AH3jOHwCQ&sa=X&oi=book_result&ct=result&resnum=5&ved=0CD8Q6AEwBA, and here http://books.google.com/books?id=tfgIGkforucC&q=%22miracles+do+not+cluster%22&dq=%22miracles+do+not+cluster%22&hl=en&ei=3D9ETs7ZNMXj0QHxkcn8CQ&sa=X&oi=book_result&ct=result&resnum=7&ved=0CEYQ6AEwBjgo, for example. A similar quote can be found in a speech by Edwin Meese, a longtime associate of Reagan, part of a 1986 book (pamphlet?), The Great debate: interpreting our written Constitution, page 56 http://books.google.com/books?id=HmVDAQAAIAAJ&q=%22miracles+do+not+cluster%22&dq=%22miracles+do+not+cluster%22&hl=en&ei=3D9ETs7ZNMXj0QHxkcn8CQ&sa=X&oi=book_result&ct=result&resnum=4&ved=0CDcQ6AEwAzgo
Webster did say, in two different places and times, words that are similar enough to be the presumable basis of this misquote, though the phrase "the Republic for which it stands" is best known from its presence in The Pledge of Allegiance http://en.wikipedia.org/wiki/Pledge_of_Allegiance, written in 1892, about 40 years after Webster died. These are Webster's words:
Hold on, my friends, to the Constitution of your country and the government established under it. Leave evils which exist in some parts of the country, but which are beyond your control, to the all-wise direction of an over-ruling Providence. Perform those duties which are present, plain and positive. Respect the laws of your country." (1851 letter from Daniel Webster to Dr. William B. Gooch of West Dennis, Massachusetts, quoted in an 1898 publication of the Bay State Monthly http://books.google.com/books?id=LNwXAQAAIAAJ&pg=PA326&dq=%22hold+on+my+friends+to+the+constitution%22&hl=en&ei=_BxEToOjI-Lb0QGewPnACQ&sa=X&oi=book_result&ct=result&resnum=5&ved=0CEEQ6AEwBA#v=onepage&q=%22hold%20on%20my%20friends%20to%20the%20constitution%22&f=false)
We live under the only government that ever existed, which was formed by the deliberate consultations of the people. Miracles do not cluster. That which has happened but once in six thousand years, cannot be expected to happen often. Such a government, once destroyed, would have a void to be filled, perhaps for centuries, with evolution and tumult, riot and despotism. (From an 1882 book http://books.google.com/books?id=DoCdsVIZzFMC&pg=PA14&dq=%22once+in+six+thousand+years%22+Webster&hl=en&ei=NjhETvblI9K_tgeU-PHDCQ&sa=X&oi=book_result&ct=result&resnum=2&ved=0CC8Q6AEwAQ, which says it is printing an oration given by Webster in 1802; similar but not exactly the same wording can be found in The Granite monthly: a magazine of literature, history and state ...: Volume 5 - Page 7 http://books.google.com/books?id=wRYXAAAAYAAJ&pg=PA7&dq=%22miracles+do+not+cluster%22&hl=en&ei=6xhETtL9NuT30gGvo834CQ&sa=X&oi=book_result&ct=result&resnum=5&ved=0CDwQ6AEwBA#v=onepage&q=%22miracles%20do%20not%20cluster%22&f=false, 1882, which said that it was printing an 1805 address given by Webster in Concord, Massachusetts.) [That Webster would use similar wording in separate orations could be expected, of course.]
The misquote is notable for the emphasis on the Constitution rather the government of the United States; for using the word "fail" (sometimes, "fall"), rather than "destroyed", which opens up a line of argument that Webster was concerned about the Constitution being misinterpreted, in legal cases; and that worldwide anarchy could result from something happening in the United States, something fairly unthinkable in the first half of the 19th century, when the United States was in no way an important country in international matters.
Misattributed

“There is a constitutional right for people to own guns, but there's also a constitutional right to life, liberty and the pursuit of happiness…”

Hillary Clinton (1947) American politician, senator, Secretary of State, First Lady

Interview with Steve Harvey, quoted in "Clinton confuses Constitution with Declaration of Independence in gun pitch" http://www.foxnews.com/politics/2016/02/25/clinton-confuses-constitution-with-declaration-independence-in-gun-pitch.html, FoxNews.com (25 February 2016)
Presidential campaign (April 12, 2015 – 2016)

“This sophism derives much, perhaps the whole, of its currency from the assumption that there is some omnipotent and sacred supremacy pertaining to a State — to each State of our Federal Union. Our States have neither more nor less power than that reserved to them in the Union by the Constitution, no one of them ever having been a State out of the Union. The original ones passed into the Union even before they cast off their British colonial dependence, and the new ones each came into the Union directly from a condition of dependence, excepting Texas; and even Texas, in its temporary independence, was never designated a State. The new ones only took the designation of States on coming into the Union, while that name was first adopted for the old ones in and by the Declaration of Independence. Therein the "United Colonies" were declared to be "free and independent States;" but even then the object plainly was not to declare their independence of one another or of the Union, but directly the contrary, as their mutual pledge and their mutual action before, at the time, and afterwards abundantly show. The express plighting of faith by each and all of the original thirteen in the Articles of Confederation, two years later, that the Union shall be perpetual is most conclusive. Having never been States, either in substance or in name, outside of the Union, whence this magical omnipotence of "State rights," asserting a claim of power to lawfully destroy the Union itself? Much is said about the "sovereignty" of the States, but the word even is not in the National Constitution, nor, as is believed, in any of the State constitutions. What is a "sovereignty" in the political sense of the term? Would it be far wrong to define it "a political community without a political superior"? Tested by this, no one of our States, except Texas, ever was a sovereignty; and even Texas gave up the character on coming into the Union, by which act she acknowledged the Constitution of the United States and the laws and treaties of the United States made in pursuance of the Constitution to be for her the supreme law of the land. The States have their status in the Union, and they have no other legal status. If they break from this, they can only do so against law and by revolution. The Union, and not themselves separately, procured their independence and their liberty. By conquest or purchase the Union gave each of them whatever of independence and liberty it has. The Union is older than any of the States, and, in fact, it created them as States. Originally some dependent colonies made the Union, and in turn the Union threw off their old dependence for them and made them States, such as they are. Not one of them ever had a State constitution independent of the Union. Of course it is not forgotten that all the new States framed their constitutions before they entered the Union, nevertheless dependent upon and preparatory to coming into the Union.”

Abraham Lincoln (1809–1865) 16th President of the United States

1860s, Fourth of July Address to Congress (1861)

“The Union is a confederation of States. But in another aspect the United States constitute only one nation.”

William H. Seward (1801–1872) American lawyer and politician

On the Irrepressible Conflict (1858)
Context: The Union is a confederation of States. But in another aspect the United States constitute only one nation. Increase of population, which is filling the States out to their very borders, together with a new and extended network of railroads and other avenues, and an internal commerce which daily becomes more intimate, is rapidly bringing the States into a higher and more perfect social unity or consolidation. Thus, these antagonistic systems are continually coming into closer contact, and collision results.
Shall I tell you what this collision means? They who think that it is accidental, unnecessary, the work of interested or fanatical agitators, and therefore ephemeral, mistake the case altogether. It is an irrepressible conflict between opposing and enduring forces, and it means that the United States must and will, sooner or later, become either entirely a slaveholding nation, or entirely a free-labor nation.