The 1918 United States Senate elections were held throughout 1918, the midpoint of Woodrow Wilson's second term as President of the United States. Republicans gained a slim 2-seat control after picking up a net 6 seats (4 in general elections and 2 in special elections). The change in control meant that the Republicans could deny entry of the United States into the League of Nations. American participation in this new international institution was the centerpiece of Wilson's post-war foreign policy.