[64] In August, Harding argued for giving Wilson almost dictatorial powers, stating that democracy had little place in time of war.[65] Harding voted for most war legislation, including the Espionage Act of 1917, which restricted civil liberties, though he opposed the excess profits tax as anti-business. In May 1918, Harding, less enthusiastic about Wilson, opposed a bill to expand the president's powers.[66]
In the 1918 midterm congressional elections, held just before the armistice, Republicans narrowly took control of the Senate.[67] Harding was appointed to the Senate Foreign Relations Committee.[68] Wilson took no senators with him to the Paris Peace Conference, confident that he could force what became the Treaty of Versailles through the Senate by appealing to the people.[67] When he returned with a single treaty establishing both peace and a League of Nations, the country was overwhelmingly on his side. Many senators disliked Article X of the League Covenant, that committed signatories to the defense of any member nation that was attacked, seeing it as forcing the United States to war without the assent of Congress. Harding was one of 39 senators who signed a round-robin letter opposing the League. 