Isolationists won the upper hand after World War I. Following the mood of public opinion, they were reluctant to keep US deep engagement in world affairs. The Senate refused to ratify the Treaty of Versailles and the treaty of the League of Nations, the cherished brainchild of president W. Wilson. As a result, the absence of the US and the lack of means to enforce its resolutions, the League of Nations was a failure. Isolationist views also made it harder to get the US join the Allied side in the early moments of WWII.
<span>The U.S mail cars were connected to the Pullman cars so they could allow federal intervention to end the strike by letting railroad executives to claim the strike interfered with the mail.</span>
