Sarah Palin has hinted at running to unseat Lisa Murkowski in 2022 should the Alaska senator fail to back president Donald Trump's Supreme Court Justice nominee.
Ms Palin, former Alaska governor and defeated GOP vice presidential candidate, used a series of social media videos to taunt Ms Murkowsi, who has held the seat since 2002.
"We sure hope that you have it within you to do the right thing this time,” Ms Palin, 56, told Ms Murkowski, referencing the latter's decision not to fall in line with GOP whips and support justice Brett Kavanaugh in 2018.
“So, you should walk back. We'll forgive you," Ms Palin added, responding to reports that Ms Murkowski, 63, was not planning to vote for Trump's pick to replace Ruth Bader Ginsburg (RBG), who died earlier this month.
"If you can't do that, remember my house? I can see a lot of things from my house... Lisa, I can see 2022 from my house," Mr Palin continued.
Mr Trump, 74, on Saturday announced Amy Coney Barrett, a conservative pro-life lawyer, as his choice to replace RBG, who was considered a liberal icon and staunch defender of women's and equal rights.
If the Republican-controlled Senate confirms Ms Barrett, 48, then it would shift the ideological balance of power in the court in favour of conservatives.
This could have implications for some of the most important and fiercely contested issues in US law, such as reproductive rights.
GOP lawmakers - against RBG's dying wish - are racing to confirm Mr Trump's pick ahead of November's election, seeing it as a way to shore up votes from America's religious communities.
The Senate is expected to begin proceedings on 12 October. To confirm Ms Barrett, Republicans need a simple majority - or 51 votes.
The GOP currently holds a slight majority of 53-47, meaning they cannot lose four votes, since a 50-50 tie would be broken by vice president Mike Pence.
