Sen. Kelly Loeffler (R-Ga.) was sworn in on Monday to succeed retiring Sen. Johnny Isakson (R).
She was sworn in on the Senate floor by Vice President Pence.
Loeffler was appointed to the seat by Georgia Gov. Brian Kemp (R) after Isakson announced he was retiring due to health reasons.
Isakson was reelected in 2016 and had been expected to serve in the Senate through 2022.
Loeffler, a former business executive, will at least serve through the end of the year when a special election will be held in November for the remainder of Isakson’s term.
Her appointment has sparked frustration among Trump’s allies and the Republican grassroots, who questioned her conservative credentials.
Rep. Doug Collins (R-Ga.) hasn’t ruled out challenging Loeffler in the special election, underscoring the tension within the party.
“We’ll make a statement or we’ll deal with that after the fact. I’m not … ruling it out,” Collins said late last month.