long series of reciprocal trade agreements, blocked deals to annex the Dominican Republic and the Danish West Indies, defeated an arbitration deal with Britain, and forced the renegotiation of the pact to build the Panama Canal. Finally, in 1898, the Senate nearly refused to ratify the treaty that ended the Spanish–American War. 1913–1945 The Senate underwent several significant changes during the presidency of Woodrow Wilson, the most profound of which was the ratification of the 17th Amendment in 1913, which provided for election of senators by popular vote rather than appointment by the state legislatures. Another change that occurred during the presidency of Woodrow Wilson was the limitation of the filibuster through the cloture vote. The filibuster was first used in the early Republic, but was seldom seen during most of the 19th century. It was limited as a response to the filibuster of the arming of merchant ships in World War I. At that time, the public, the House, the great majority of the Senate, and the president wanted merchant ships armed, but less than 20 Senators, led by William Jennings Bryan fought to keep US ships unarmed. Wilson denounced the group as a "group of willful men". The post of Senate Majority Leader was also created during the Wilson presidency. Before this time, a Senate leader was usually a committee chairman, or a person of great eloquence, seniority, or wealth, such as Daniel Webster and Nelson Aldrich. However, despite this new, formal leadership structure, the Senate leader initially had virtually no power, other than priority of recognition from the presiding officer. Since the Democrats were fatally divided into northern liberal and southern conservative blocs, the Democratic leader had even less power than his title suggested. Rebecca Felton was sworn in as a Senator for Georgia on November 21, 1922, and served one day; she was the first woman to serve in the Senate. Joseph T. Robinson of Arkansas, the Democratic leader from 1923 to 1937, saw it as his responsibility not to lead the Democrats, but to work the Senate for the president's benefit, no matter who the president was. When Coolidge and Hoover were president, he assisted them in passing Republican legislation. Robinson helped end government operation of Muscle Shoals, helped pass the Hoover Tariff, and stymied a Senate investigation of the Power Trust. Robinson switched his own position on a drought relief program for farmers when