For the United States to abide by the Treaty, and be brought into the League of Nations, Senatorial ratification was required. The Senate Committee on Foreign Relations, chaired by Henry Cabot Lodge of Massachusetts, rejected the Treaty on the grounds that it proposed that the US would join France immediately if they were again attacked by Germany, essentially engaging the US in an "Entangling Alliance." Ironically, Germany also refused to sign the document, due to the famous "War Guilt" clause, and held off until The Allies threatened invasion. The US never ratified the treaty; Woodrow Wilson, who had labored so hard to advance the League, warned that "Arrangements of the present peace cannot stand a generation unless they are guaranteed by the united forces of the civilized world."
A History of the Modern World, Palmer & Colton, pg. 684, 1978.
Rise of the American Nation, Todd / Curti, pg. 646, 1972.
Sign? Yes, initially. Ratify? No.
That is to say, President Wilson played a major role in shaping the treaty; it was in part an American treaty, agreed to by others and imposed on some, such as Germany.
However, Congress refused to pass it without changes, and Wilson would not commit to holding to it without support from the rest of the government.
The usa did not sign the treaty, because it would have lead them in war in case france was ever attacked
We(The United States) never ratified the treaty and in fact we never even joined the League of Nations. If we did sign it it would lead us to war