“I have a strong belief that there is a danger of the public opinion of this country undergoing a reaction from the Cobdenic doctrines of 30 or 40 years ago, and believing that it is our duty to take everything we can, to fight everybody, and to make a quarrel of every dispute. That seems to me a very dangerous doctrine, not merely because it might incite other nations against us—though that is not a consideration to be neglected, for the kind of reputation we are at present enjoying on the Continent of Europe is by no means pleasant, and by no means advantageous; but there is a much more serious danger, and that is lest we should overtax our strength. However strong you may be, whether you are a man or a nation, there is a point beyond which your strength will not go. It is madness; it ends in ruin if you allow yourselves to pass beyond it.”

On Fox News Sunday http://web.archive.org/web/20070114221322/http://www.cnn.com/2007/POLITICS/01/14/US.iraq.ap/index.html responding to the opposition against sending 21,500 more troops to Iraq (January 14, 2007)
2000s, 2007

1910s, Address to the Knights of Columbus (1915)
Context: Four centuries and a quarter have gone by since Columbus by discovering America opened the greatest era in world history. Four centuries have passed since the Spaniards began that colonization on the main land which has resulted in the growth of the nations of Latin-America. Three centuries have passed since, with the settlements on the coasts of Virginia and Massachusetts, the real history of what is now the United States began. All this we ultimately owe to the action of an Italian seaman in the service of a Spanish King and a Spanish Queen. It is eminently fitting that one of the largest and most influential social organizations of this great republic, a republic in which the tongue is English, and the blood derived from many sources, should, in its name, commemorate the great Italian. It is eminently fitting to make an address on Americanism before this society. We of the United States need above all things to remember that, while we are by blood and culture kin to each of the nations of Europe, we are also separate from each of them. We are a new and distinct nationality. We are developing our own distinctive culture and civilization, and the worth of this civilization will largely depend upon our determination to keep it distinctively our own. Our sons and daughters should be educated here and not abroad. We should freely take from every other nation whatever we can make of use, but we should adopt and develop to our own peculiar needs what we thus take, and never be content merely to copy.

Speech http://hansard.millbanksystems.com/lords/1962/aug/02/britain-and-the-common-market in the House of Lords on the British application to join the Common Market (2 August 1962).
Later life

Stated http://www.fas.org/news/iraq/1998/02/19/98021907_tpo.html on NBC's Today Show (February 19, 1998)
1990s

is equally relevant.
The World's Last Night (1952)

Quoted in Bear Grylls impressed with Modi’s 'humility'; says PM calm during crisis, agreed to sit in homemade raft https://economictimes.indiatimes.com/magazines/panache/bear-grylls-impressed-with-modis-humility-says-pm-calm-during-crisis-agreed-to-sit-in-homemade-raft/articleshow/70615908.cms Bear Grylls
2019

Letter to William Charles Jarvis (1820)
1820s
Context: You seem to consider the federal judges as the ultimate arbiters of all constitutional questions, a very dangerous doctrine, indeed, and one which would place us under the despotism of an oligarchy. Our judges are as honest as other men, and not more so. They have with others the same passions for the party, for power and the privilege of the corps. Their power is the more dangerous, as they are in office for life and not responsible, as the other functionaries are, to the elective control. The Constitution has erected no such single tribunal, knowing that to whatever hands confided, with the corruptions of time and party, its members would become despots. It has more wisely made all departments co-equal and co-sovereign within themselves.

Reported as refuted in the Congressional Record: Lou Hiner, Jr., "Hitler's Phony Quotation on Law and Order", May 21, 1970, vol. 116, pp. 1676–77, reprinted from the Indianapolis News; and M. Stanton Evans, "The Hitler Quote", August 11, 1970, vol. 116, p. 28349, reprinted from the National Review Bulletin (August 18, 1970).
Misattributed