The seventeenth amendment specifies that U.S. senators are to be “elected by the people” instead of by state legislatures, as originally provided by the 1787 Constitution. Ratification came after more than two decades of sustained, organized mobilization by ordinary Americans outraged by the corruption of state legislators who sold Senate seats to the highest bidders. The hitch? Section 2 of the Seventeenth Amendment permits appointment by governors in the event of a vacancy: “The executive authority of each state shall issue writs of election to fill such vacancies: provided that the legislature of any state may empower the executive thereof to make temporary appointments until the people fill the vacancies by election as the legislature may direct.”
The vacancy language is left over from the old legislative-appointment system, under which governors could appoint temporary senators “until the next Meeting of the Legislature.” Those “temporary appointments” were limited in time—they could not last beyond the next legislative session, which was already set by state law. But the drafters of the Seventeenth Amendment, for whatever reason, specified “temporary appointments until the people fill the vacancies by election as the legislature may direct.”
See the difference? The special Senate election has no firm deadline, and the language could even be read to allow a “temporary appointment” to substitute completely for a special election.