Ms. Murkowski was the only Senate Republican up for re-election this year who voted to convict Mr. Trump, a move that prompted a fierce backlash from Republicans in her state. She has also frustrated her party by supporting Democratic nominees for the Supreme Court and for positions in President Biden's administration.
She has played a key role in negotiating several bipartisan compromises, including the $1 trillion infrastructure law, which she highlighted in several appearances across her state. Ms. Murkowski, one of just two Senate Republicans who support abortion rights, has expressed support for codifying abortion rights after the Supreme Court overturned Roe v. Wade and openly expressed her dismay over the decision.
Ms. Tshibaka had sought to capitalize on conservative wrath against Ms. Murkowski, who retained the backing of Senator Mitch McConnell of Kentucky, the minority leader, and his allies. But the use of ranked-choice voting, as well as an open primary system that sent the top four candidates regardless of party through to the general election, was championed by some of her allies in part to help centrist candidates like Ms. Murkowski.