Final answer:
Progressive reformers supported the 17th Amendment to ensure fairer representation and to eliminate corruption in the selection of U.S. senators, which had been controlled by state legislatures. Influential advocates like William Jennings Bryan played a key role in the amendment's passage, which was part of a larger effort to increase direct democracy and citizen involvement in government.
Step-by-step explanation:
Why Progressive Reformers Supported the 17th Amendment
Progressive reformers supported the 17th Amendment because they sought to enhance democratic reform within the federal government and achieve fairer representation for the state constituencies in the U.S. Congress. Influential figures like William Jennings Bryan advocated for the amendment, aiming to eradicated unfair practices and corruption associated with the selection of U.S. senators by state legislatures. The progression towards direct election of senators was part of a broader movement which included direct primary, initiative, referendum, and recall to increase citizen participation in the electoral process and government. This change was catalyzed by scandalous elections in which senators were often perceived to have been chosen due to their relationships with legislators rather than on merit, undermining public trust.
The Seventeenth Amendment was designed as a remedy to this and an extension of more democratic principles, aligning the Senate election process with that of the House of Representatives, the latter of which had already moved to direct elections. This shift not only promised to make the government more responsive to the will of the people, but it also was a means to address issues of cronyism and the influence of business and special interests within the Senate.