Lisa Murkowski, Alaska’s moderate Republican senator, announced early on Friday that she will not vote for Donald Trump’s nomination of Todd Blanche as US attorney general, leaving his elevation from “acting” to official confirmation in the post even narrower.

Murkowski issued a statement expressing her concerns that the Trump administration could proceed with its proposed fund to compensate rioters who invaded the US Capitol on January 6 in a failed attempt to overturn Joe Biden’s defeat of Trump in the 2020 presidential election.

She took her stance even though Blanche confirmed in writing the controversial fund was dead. Experts say Trump could easily reverse it. Murkowski said the Senate only currently has leverage over the fund because Blanche’s nomination to head the Department of Justice is pending necessary confirmation by the upper congressional chamber.

Blanche had persuaded the Senate judiciary committee in a 12-10 vote in his favor earlier this week only because he promised Republican holdouts that he would not pursue the payout fund.

Blanche issued a formal order late on Sunday terminating Trump’s $1.8bn “anti-weaponization” slush fund designed to compensate political allies who had been “targeted” by the justice department, including prosecutions of January 6 insurrectionists. That move followed weeks of negotiations with two Republican senators who were blocking his nomination to become attorney general – Thom Tillis and John Cornyn, who were eventually swayed by Blanche.

Murkowski posted on X on Friday, praising Blanche but then saying “ultimately” she would oppose his nomination, a position she took on Tuesday and is now sticking with.

“The country needs an Attorney General who will check the worst impulses of this administration. I hope Mr Blanche is able to achieve that, if confirmed, but I simply do not have confidence that will be the case,” she wrote, as part of a much longer post on the topic.

Republicans hold a 53-47 Senate majority, but Mitch McConnell of Kentucky is not currently attending sessions because of his health, giving the GOP little room to lose senators and still confirm the president’s pick.

The Associated Press contributed reporting.