“During the last six years the United States Army has not only matured greatly, but its officers have grown vastly more aware of their world-wide responsibilities as military men. Allied command has become the accepted pattern of military operation, and many of the insular differences that once caused us to question the motives of our allies have now been completely resolved.”

1920s, Ways to Peace (1926)
Context: Fellow Americans, this Nation approaches no ceremony with such universal sanction as that which is held in commemoration over the graves of those who have performed military duty. In our respect for the living and our reverence for the dead, in the unbounded treasure which we have poured out in bounties, in the continual requiem services which we have held, America at least has demonstrated that republics are not ungrateful. It is one of the glories of our country that so long as we remain faithful to the cause of justice and truth and liberty, this action will continue. We have waged no wars to determine a succession, establish a dynasty, or glorify a reigning house. Our military operations have been for the service of the cause of humanity. The principles on which they have been fought have more and more come to be accepted as the ultimate standards of the world. They have been of an enduring substance, which is not weakened but only strengthened by the passage of time and the contemplation of reason.

Source: Introduction, p. viii note: 1950s, Fleet Admiral King: A Naval Record (1952)

As quoted in The New York Times (6 July 1973).

2011, Address on interventions in Libya (March 2011)

About the Medal of Honor awardees. Quoted in "Rising Sons" - Page 260 - by Bill Yenne - History - 2007

2011, Address on interventions in Libya (March 2011)
Context: As Commander-in-Chief, I have no greater responsibility than keeping this country safe. And no decision weighs on me more than when to deploy our men and women in uniform. I’ve made it clear that I will never hesitate to use our military swiftly, decisively, and unilaterally when necessary to defend our people, our homeland, our allies and our core interests. That's why we’re going after al Qaeda wherever they seek a foothold. That is why we continue to fight in Afghanistan, even as we have ended our combat mission in Iraq and removed more than 100,000 troops from that country. 
There will be times, though, when our safety is not directly threatened, but our interests and our values are. Sometimes, the course of history poses challenges that threaten our common humanity and our common security — responding to natural disasters, for example; or preventing genocide and keeping the peace; ensuring regional security, and maintaining the flow of commerce. These may not be America’s problems alone, but they are important to us. They’re problems worth solving. And in these circumstances, we know that the United States, as the world’s most powerful nation, will often be called upon to help.
In such cases, we should not be afraid to act — but the burden of action should not be America’s alone. As we have in Libya, our task is instead to mobilize the international community for collective action. Because contrary to the claims of some, American leadership is not simply a matter of going it alone and bearing all of the burden ourselves. Real leadership creates the conditions and coalitions for others to step up as well; to work with allies and partners so that they bear their share of the burden and pay their share of the costs; and to see that the principles of justice and human dignity are upheld by all.

Turkey and PKK
Source: http://www.time.com/time/world/article/0,8599,1680302,00.html?xid=feed-cnn-topics

2000s, 2003, Mission Accomplished (May 2003)

Source: From the Danube to the Yalu (1954), p. 176