Which group was most justified in its reaction to the treaty? why? main ideas 3. what was the goal of woodrow wilson's fourteen points? 4. what was the "war guilt" clause in the treaty of versailles? 5. why did the united states reject the treaty of versailles?

You bunched a lot of questions together. Let me handle just a couple of them - #3 and #5.

The goal of Wilson's "Fourteen Points" speech, delivered before Congress in January, 1918, was to set forth plans for how to set things right after the Great War concluded.  He hoped his points could serve as an outline for peace negotiations and as a plan for securing world peace going forward.  Self-determination by peoples of their own governments was a key concern, as was reduction of armaments by nations.  And -- the big idea in Point #14 -- an international "association of nations must be formed under specific covenants for the purpose of affording mutual guarantees of political independence and territorial integrity to great and small states alike."

This last point -- which led to the establishment of the League of Nations -- is also why the United States Senate refused to ratify the Treaty of Versailles. There were many in the United States who felt we should not commit ourselves to a form of governance by any external body such as the League of Nations would be.  You'll still hear some voices like that in American politics today, who object to the United States' participation in the United Nations.  (After World War II, the United Nations was established.)