“After the spiritual powers, there is no thing in the world more unconquerable than the spirit of nationality. … The spirit of nationality in Ireland will persist even though the mightiest of material powers be its neighbor.”

Quotes, NYU Speech (2004)
Context: These horrors were the predictable consequence of policy choices that flowed directly from this administration's contempt for the rule of law. And the dominance they have been seeking is truly not simply unworthy of America — it is also an illusory goal in its own right.
Our world is unconquerable because the human spirit is unconquerable, and any national strategy based on pursuing the goal of domination is doomed to fail because it generates its own opposition, and in the process, creates enemies for the would-be dominator.
A policy based on domination of the rest of the world not only creates enemies for the United States and creates recruits for Al Qaeda, it also undermines the international cooperation that is essential to defeating the efforts of terrorists who wish harm and intimidate Americans.

Source: A Child Called "It"

1910s, Address to the Knights of Columbus (1915)
Context: There must be not merely preparedness in things material; there must be preparedness in soul and mind. To prepare a great army and navy without preparing a proper national spirit would avail nothing. And if there is not only a proper national spirit, but proper national intelligence, we shall realize that even from the standpoint of the army and navy some civil preparedness is indispensable. For example, a plan for national defense which does not include the most far-reaching use and cooperation of our railroads must prove largely futile. These railroads are organized in time of peace. But we must have the most carefully thought out organization from the national and centralized standpoint in order to use them in time of war. This means first that those in charge of them from the highest to the lowest must understand their duty in time of war, must be permeated with the spirit of genuine patriotism; and second, that they and we shall understand that efficiency is as essential as patriotism; one is useless without the other.

Prologue
The Path of the King (1921)
Context: Generations follow, oblivious of the high beginnings, but there is that in the stock which is fated to endure. The sons and daughters blunder and sin and perish, but the race goes on, for there is a fierce stuff of life in it. It sinks and rises again and blossoms at haphazard into virtue or vice, since the ordinary moral laws do not concern its mission. Some rags of greatness always cling to it, the dumb faith that sometime and somehow that blood drawn from kings it never knew will be royal again. Though nature is wasteful of material things, there is no waste of spirit. And then after long years there comes, unheralded and unlooked-for, the day of the Appointed Time...

1940s, Third Inaugural Address (1941)
Context: But it is not enough to achieve these purposes alone. It is not enough to clothe and feed the body of this Nation, and instruct and inform its mind. For there is also the spirit. And of the three, the greatest is the spirit. Without the body and the mind, as all men know, the Nation could not live. But if the spirit of America were killed, even though the Nation's body and mind, constricted in an alien world, lived on, the America we know would have perished.

Source: Dictionary of Burning Words of Brilliant Writers (1895), P. 137.

1990s, A Distinctly American Internationalism (November 1999)

Quoted in "Dragon in the Dust" - Page 229 - by Post Wheeler - 2007