A House Republican who has been critical of rushing to impeach President Biden is calling for his removal over questions about his mental fitness for the job.

Rep. Ken Buck, R-Colo., told Fox News Digital that he plans to introduce a resolution on Monday to call on Biden’s Cabinet to invoke the 25th Amendment of the Constitution. 

His most-cited reason was Special Counsel Robert Hur’s report on Biden’s handling of classified documents. The report did not recommend any charges for the president but repeatedly painted him as an aging leader with a poor memory.

Buck said the report ‘addressed what many Americans have long witnessed with their own eyes – that President Biden is no longer fit to successfully discharge the critical duties of his office.’

‘Numerous instances were articulated in the report, and have played out in full public view, showing President Biden’s apparent cognitive decline and lack of mental stamina,’ he told Fox News Digital.

‘The societal challenges and security threats our country faces are innumerable and require a chief executive with both strong mental and physical faculties. The time has come for the vice president and the Cabinet to put our country first and move forward on invoking the 25th Amendment.’

In his resolution text, Buck also cited Biden’s verbal stumbles and public gaffes as evidence of mental decline. It pointed out that Biden recently confused French President Emmanuel Macron with a predecessor who died decades prior, and that he also mixed up German leaders’ names and mistakenly referred to the president of Egypt as the president of Mexico.

Biden and his allies have vigorously denied that his mental acuity is suffering.

But Buck’s resolution is a significant addition to the growing pressure for Biden officials to address scrutiny over the president’s mental fitness. 

The Colorado Republican, who is retiring at the end of this term, is one of the few House GOP lawmakers who have publicly expressed wariness over the push to impeach Biden over allegations that he and his family’s businesses profited off of his political weight.

Buck voted along with the rest of the House GOP Conference to formalize the Biden impeachment inquiry in December, but just last week he criticized the probe’s leaders for relying on allegations made by FBI informant Alexander Smirnov, who was recently indicted for lying to the bureau.

‘We’ve always been looking for a link between what Hunter Biden received in terms of money and Joe Biden’s activities or Joe Biden receiving money. This clearly is not a credible link at this point,’ Buck said in a CNN interview.

He told the network in September, ‘I want to make sure we don’t ruin this institution over a tit-for-tat impeachment. If the evidence is there… I will absolutely vote for impeachment. I don’t see the evidence at this point.’

Section 4 of the 25th Amendment allows the vice president and a majority of the White House Cabinet to declare the president unfit to perform his duties, transferring power to the vice president. 

The president is able to take those powers back by writing to Congress that he is able to serve. The Cabinet would then have four days to refute that, after which Congress would vote on whether the president could remain in power.

Buck is one of several Republican lawmakers who have called for the constitutional amendment to be invoked in the wake of Hur’s report, including Sens. Rick Scott, R-Fla., and Mike Lee, R-Utah, as well as Reps. Mary Miller, R-Ill., and Mike Collins, R-Ga.

Fox News Digital has reached out to the White House for comment on Buck’s resolution.