After WWI, the Allied powers and Germany negotiated the Treaty of Versailles in 1919. The treaty imposed harsh terms on Germany, including war guilt, military limitations, and territorial losses. It failed to reconcile the countries or establish lasting peace. The US Senate rejected American participation in the League of Nations, leaving the country isolated. Radical groups conducted bombings in the postwar unrest, leading to a crackdown on suspected communists under the Palmer Raids. Overall, the treaty settlements exacerbated tensions instead of healing wounds from the war.