I am trying to tell the people what is in the treaty. You would not know what was in it to read some of the speeches I read, and if you will be generous enough to me to read some of the things I say, I hope it will help to clarify a great many matters which have been very much obscured by some of the things which have been said. Because we have now to make the most critical choice we ever made as a nation, and it ought to be made in all soberness and without the slightest tinge of party feeling in it. I would be ashamed of myself if I discussed this great matter as a Democrat and not as an American. I am sure that every man who looks at it without party prejudice and as an American will find in that treaty more things that are genuinely American than were ever put into any similar document before.
The chief thing to notice about it, my fellow citizens, is that it is the first treaty ever made by great powers that was not made in their own favor. It is made for the protection of the weak peoples of the world and not for the aggrandizement of the strong. That is a noble achievement, and it is largely due to the influence of such great peoples as the people of America, who hold at their heart this principle, that nobody has the right to impose sovereignty upon anybody else; that, in disposing of the affairs of a nation, that nation or people must be its own master and make its own choice. The extraordinary achievement of this treaty is that it gives a free choice to people who never could have won it for themselves. It is for the first time in the history of international transactions an act of systematic justice and not an act of grabbing and seizing.
If you will just regard that as the heart of the treaty—for it is the heart of the treaty—then everything else about it is put in a different light. If we want to stand by that principle, then we can justify the history of America as we can in no other way, for that is the history and principle of America. That is at the heart of it. I beg that, whenever you consider this great matter, you will look at it from this point of view: Shall we or shall we not sustain the first great act of international justice? The thing wears a very big aspect when you look at it that way, and all little matters seem to fall away and one seems ashamed to bring in special interests, particularly party interests. What difference does party make when mankind is involved? Parties are intended, if they are intended for any legitimate purpose, to serve mankind, and they are based upon legitimate differences of opinion, not as to whether mankind shall be served or not, but as to the way in which it shall be served; and, so far as those differences are legitimate differences, party lines are justified.
Woodrow Wilson, Address from Rear Platform in Richmond, Indiana Online by Gerhard Peters and John T. Woolley, The American Presidency Project https://www.presidency.ucsb.edu/node/317805