The framers of the Constitution, believing that senators could act more independently if not popularly elected, made state legislatures responsible for choosing U.S. senators. This system had unintended consequences, including bribery of state legislators and party deadlocks, which resulted in vacant Senate seats. The call for direct election of senators first arose in 1826 and continued for 86 years, gaining momentum after Oregon officially began selecting senators through a popular referendum in 1908. Congress finally approved a resolution for direct election of senators, and the states ratified it as the Seventeenth Amendment in 1913.
I have faith in the judgment of the great mass of the American people and believe that they will eagerly avail themselves of the opportunity to bring the Senate nearer to the people and make it more quickly responsive to the public will, and that the amendment will be speedily ratified.
Senator Joseph Bristow of Kansas, Speech to the U.S. Senate, May 15, 1912