WASHINGTON — Republican Sen. Lisa Murkowski said Saturday she “could not” vote for former President Donald Trump in the 2024 election should he win her party’s nomination again — but that also doesn’t mean she could cross party lines for President Joe Biden, either.

“I could not” vote for Trump, Murkowski said in a phone call with NBC News on Saturday night, adding, “I can’t vote for Biden.”

She urged those like her who want an alternative not to “quit” on former South Carolina Gov. Nikki Haley’s long-shot GOP bid yet.

“I want to encourage everyone who believes that America is better than just a re-do of what we have from 2020,” the Alaska senator said just ahead of her state’s primary on Super Tuesday and one day after she endorsed Haley. “I don’t want to see that white flag raised.”

Pressed on why not, she said simply, “Why not? … It’s not just a situation where Nikki is the lesser of the evils. She is a qualified, competent, capable leader at a time when the country needs them. I refuse to accept that [Trump and Biden are] my only two choices.”

Murkowski endorsed Haley on Friday and was followed soon after by a fellow Trump critic in the upper chamber, Sen. Susan Collins, R-Maine.

Murkowski, who previously admitted that she also didn’t vote for Trump in 2020, voted to convict him on impeachment charges after the Jan. 6, 2021, insurrection. Trump, who was acquitted of those charges, then backed a primary challenger who unsuccessfully ran against Murkowski in 2022.

Now, as Murkowski backs an opponent in Trump’s race, questions are emerging about the viability of Haley’s candidacy, given the former United Nations ambassador’s inability as of yet to win a primary. If Haley were to drop out, Murkowski says that she — and others — would be unsure of what to do in the 2024 election.

“Lisa Murkowski is not the only one in this camp right now,” Murkowski said.