Delivered today at the Truman Presidential Library in Independence Missouri. [Full Text from BBC News]
That is why this country has historically been in the vanguard of the global human rights movement. But that lead can only be maintained if America remains true to its principles, including in the struggle against terrorism.
When it appears to abandon its own ideals and objectives, its friends abroad are naturally troubled and confused.
And states need to play by the rules towards each other, as well as towards their own citizens. That can sometimes be inconvenient, but ultimately what matters is not convenience. It is doing the right thing.
No state can make its own actions legitimate in the eyes of others. When power, especially military force, is used, the world will consider it legitimate only when convinced that it is being used for the right purpose - for broadly shared aims - in accordance with broadly accepted norms.
No community anywhere suffers from too much rule of law; many do suffer from too little - and the international community is among them. This we must change.
The US has given the world an example of a democracy in which everyone, including the most powerful, is subject to legal restraint. Its current moment of world supremacy gives it a priceless opportunity to entrench the same principles at the global level.
As Harry Truman said, "We all have to recognise, no matter how great our strength, that we must deny ourselves the licence to do always as we please."