Ratified in 1913, the Seventeenth Amendment established direct popular election of two senators from each state. The voters qualified to choose the most numerous branch of a state's legislature also qualify to vote for senator. This was a structural change in representation: authority moved from state legislatures to statewide electorates. It was not a ban on discrimination comparable to the Fifteenth, Nineteenth, Twenty-Fourth, or Twenty-Sixth Amendments.

The amendment changed the method of selection without redesigning the Senate. Every state still has two senators, each senator still serves a six-year term, and the seats remain divided into staggered classes. California does not gain more senators than Wyoming because it casts more votes. Nor is Senate representation proportional to a party's national vote share. Each state is a separate statewide constituency, and only part of the Senate normally faces election in a given cycle.

Vacancies require one more distinction. The amendment directs the state's executive authority to issue a writ of election. A state legislature may also authorize the executive to make a temporary appointment until voters fill the vacancy as state law directs. The governor therefore has no unlimited national power to appoint a senator under every circumstance. The authority and timing depend on the amendment and the state's implementing law.

Direct election strengthened voters' ability to reward or replace senators, but it did not make senators legally bound delegates of current opinion polls. Senators retain constitutional duties involving legislation, appointments, treaties, and impeachment trials. The amendment also did not replace the Electoral College: voters directly select senators, while presidential elections operate through electors under a different constitutional system. When a problem mentions legislative selection, a direct statewide Senate contest, or a temporary Senate vacancy, identify the selector first. That single question usually reveals whether the Seventeenth Amendment is the governing rule.

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