Why did progressives support the 17th Amendment?
Subsequently, one may also ask, why was the 17th amendment needed?
Passed by Congress May 13, 1912, and ratified April 8, 1913, the 17th amendment modified Article I, section 3, of the Constitution by allowing voters to cast direct votes for U.S. Senators. The Constitution, as it was adopted in 1788, made the Senate an assembly where the states would have equal representation.
Keeping this in view, who supported the 17th Amendment?
Senator William Borah of Idaho, himself a product of a state-based system of direct election, strongly supported the measure. In fact, by 1912, as many as 29 states elected U.S. senators either as nominees of their party's primary or in a general election.
In the same way that many legislatures have eagerly handed over redistricting powers to nonpartisan commissions, they sought to outsource the selection of senators. The 17th Amendment was embraced by legislators and the public as a way to both reduce corruption and take a divisive issue off legislators' agendas.