Trump endorses Murkowski challenger

Former President Donald Trump officially endorsed a Republican challenger to Sen. Lisa Murkowski (R-Alaska) on Friday, escalating his campaign against the longtime GOP senator who voted to convict him following his impeachment trial earlier this year.

Trump backed Kelly Tshibaka, the former state commissioner of administration, in a statement in which he called Murkowski "bad for Alaska."

"Murkowski has got to go!" Trump said in the statement.

"Kelly Tshibaka is the candidate who can beat Murkowski — and she will. Kelly is a fighter who stands for Alaska values and America First," Trump added.

Trump also said that he looked forward to campaigning for Tshibaka in Alaska. Tshibaka launched her bid in March and hired several alums of Trump's 2020 campaign in her effort to unseat the GOP senator.

Trump has already backed several Republicans in open races where GOP senators are retiring. But this marks his first endorsement of a candidate seeking to unseat a sitting Republican senator. It could cause a headache for Republicans seeking to win back the Senate majority.

Murkowski has been one of the most vocal Republican critics of Trump, and the former president vowed to oppose her reelection after she voted to convict him as part of his impeachment trial in February. She was the only Republican who is up for reelection next year who voted to convict Trump.

A spokesperson for the National Republican Senatorial Committee did not comment but pointed to the committee's previous endorsement of Murkowski. Senate Leadership Fund, a super PAC aligned with Senate Minority Leader Mitch McConnell, also endorsed Murkowski in April. A spokesperson for Murkowski did not immediately respond to a request for comment.

Intraparty challenges aren't a new hurdle for Murkowski. She lost a GOP primary challenge in 2010 but launched a historic write-in campaign for the general election and won another term. She won a much less dramatic reelection in 2016.

The Alaska race will prove a complicated test of Murkowski's support in the state. Alaska implemented a ranked-choice voting system in which all candidates run in one primary and the top four advance to the general election, where voters rank their preferences.