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    The basics

    What: Republican primary runoff election for a US Senate seat
    Why: To replace former US Sen. Jeff Sessions of Alabama, who now serves as US Attorney General
    When: Tues., Sept. 26, 2017; special election on Tues., Dec. 12, 2017
    Who: US Sen. Luther Strange vs. ex-state Supreme Court Chief Justice Roy Moore
    Details: Strange, a former Alabama Attorney General, was appointed to temporarily replace Sessions in the US Senate after Sessions became US Attorney General. Moore served twice as Alabama Supreme Court Chief Justice. He was ousted both times after controversies surrounding his opinions about same-sex marriage and the placement of a monument of the Ten Commandments in a state government building. The winner of the GOP primary faces Democrat and former US District Attorney Doug Jones in the special election.