“It is harder for a poor man to enter the United States Senate than for a rich man to enter Heaven.”

Late-19^th-century political aphorism
critiquing the Senate as a "millionaire’s club"

The Constitution, as it was adopted in 1788, made the Senate an assembly where the states would have equal representation. Each state legislature would elect 2 senators to a 6-year term. Late in the 19th century some state legislatures deadlocked over the election of a senator when different parties controlled different houses, and Senate vacancies could last months or years. In other cases, special interests or political machines gained control over the state legislature. Progressive reformers dismissed individuals elected by such legislatures as puppets and the Senate as a "millionaire’s club" serving powerful private interests.

One Progressive response to these concerns was the "Oregon system" which utilized a state primary election to identify the voters’ choice for senator while pledging all candidates for the state legislature to honor the primary’s result. Over half of the states adopted the "Oregon system," but the 1912 Senate investigation of bribery and corruption in the election of Illinois Senator William Lorimer indicated that only a constitutional amendment mandating the direct election of senators by a state’s citizenry would allay public demands for reform.