The appointment is short; Ms. Loeffler has to defend her seat in a special election on Nov. 3. As the incumbent carrying the governor’s blessing, however, she seemed to have an edge on opponents.
But President Trump had made it known that he wanted Mr. Kemp to appoint Representative Doug Collins, a hard-charging conservative who defended Mr. Trump at his impeachment. Soon Mr. Collins, too, jumped in the race.
The special election will not be preceded by primaries. Rather, it will be a free-for-all pitting the Republican candidates against a number of Democrats, including the Rev. Raphael Warnock, who pastors the Atlanta church once led by the Rev. Dr. Martin Luther King Jr., and Matt Lieberman, the son of former Senator Joe Lieberman of Connecticut.
If no candidate earns a majority of the votes, the top two vote-getters will face off in a January runoff, which has set up a primary-like atmosphere for Ms. Loeffler and Mr. Collins, with each trying to out-conservative the other, and Ms. Loeffler cultivating a new image as a right-wing firebrand.
The change in Ms. Loeffler’s public persona has been striking. She is married to Jeffrey C. Sprecher, the chairman of the New York Stock Exchange. As a spokeswoman for Intercontinental Exchange, the commodities and financial exchange company Mr. Sprecher founded in 2000, her name appeared regularly on business-wire news releases. In 2011, when she became a co-owner of the Atlanta Dream, the city’s W.N.B.A. franchise, she was praised, in local news stories, for supporting women’s athletics.
The couple’s names appeared on lists of charity donors, their photos on websites from fund-raising galas. In 2011, they planned an event for Mitt Romney, the 2012 Republican presidential candidate, who has since become a villain among Trump supporters for voting to convict the president during his Senate impeachment trial. (Ms. Loeffler was also named, in 2012, to Mr. Romney’s Georgia finance team.)