Final answer:
The Seventeenth Amendment was prompted by public dissatisfaction with senatorial selection by state legislatures, scandalous elections, and underrepresentation in one-party states, leading to the direct election of U.S. Senators to expand democracy.
Step-by-step explanation:
The conditions that preceded the Seventeenth Amendment and necessitated its passage were largely a result of public dissatisfaction with the previous method of senatorial selection. Prior to the amendment, U.S. Senators were elected by state legislatures, which led to a series of scandalous elections and a perception that senators were often chosen for their personal connections rather than qualifications. The prevalence of one-party states in the South contributed to a lack of representation for significant portions of the population. This situation, along with the growth and change in political parties, and the desire to expand democracy to allow for direct election of senators by the people, created the momentum for change. The Seventeenth Amendment was seen as a rectification of these issues by establishing that senators would be directly elected by the voters, much like representatives in the House.