Republican US Senator Bill Cassidy will vote to confirm Donald Trump’s choice for attorney general, likely saving a nomination on the precipice of defeat.

President Trump picked Todd Blanche, his former personal defence attorney who is currently acting attorney general, to run the US Department of Justice on a permanent basis.

Blanche’s success hinged on Cassidy after two Republican colleagues announced their opposition.

“This is not a referendum on President Trump, it is a decision regarding Mr Blanche, in very specific circumstances,” said Cassidy on Friday morning. “All considered, I will vote for Mr Blanche.”

Washington anxiously waited for Cassidy’s decision, due to years of acrimony between Trump and the senator.

During Trump’s second impeachment in 2021, Cassidy voted to convict Trump over the 6 January 2021 Capitol riot. The vote did not pass, and when Trump returned to office, he successfully forced Cassidy into retirement by backing a primary challenger for his Louisiana Senate seat earlier this year.

In a speech on the Senate floor, Cassidy said Blanche exercised “poor judgement” when he authorised a controversial anti-weaponisation fund and an exemption from federal tax audits as part of a settlement between Trump and the government.

Cassidy acknowledged Trump is the ultimate decider on the direction of the justice department, but that Senate confirmation would give Blanche “greater leverage to push for things that should be pushed for.”

Cassidy also said he was reluctant to impede the department’s work fighting violent crime.

“This is great news and we look forward to [Blanche’s] final confirmation shortly,” White House spokeswoman Lauren Bis said in a statement.

Earlier on Friday, Republican Senator Lisa Murkowski announced she would oppose Blanche, citing concerns over the “politicisation” of the justice department.

“The politicization – even weaponization – of the Department did not start with this administration but has accelerated during it,” Murkowski wrote on X.

Blanche’s confirmation was briefly in jeopardy on Friday morning following Murkowski’s announcement.

“While we are not surprised by Senator Murkowski’s decision, it is nevertheless disappointing, considering all the Administration and specifically the Department of Justice has done for Alaska,” press secretary Karoline Leavitt said in a statement at the time.

Blanche was already deputy attorney general when he took up the interim leadership role in April, after Pam Bondi was fired.

In her statement on X, Murkowski cited controversies that occurred during Blanche’s leadership, including the administration’s handling of the Epstein files and the “anti-weaponisation fund”.

“The country needs an Attorney General who will check the worst impulses of this administration,” Murkowski wrote.

“I hope Mr Blanche is able to achieve that, if confirmed, but I simply do not have confidence that will be the case.”

Blanche previously pledged to walk back the nearly $2bn fund after blowback from Republican senators during his confirmation hearings.

The fund was planned to provide compensation to individuals who alleged government persecution but critics including Murkowski feared it would go to individuals who were prosecuted for participating in the January 6 attack on Congress.

Trump and Blanche said the president and his family could not draw on the fund.

Another condition of the IRS settlement gave Trump certain immunity from audits.

Senator Susan Collins, a Maine Republican facing a tough re-election battle this year, this week said she would not vote for Blanche.