Donald Trump’s push to fire a top Federal Reserve official is heading for a high-stakes legal battle, which will be a litmus test for the independence of the world’s most important central bank.

Speaking at a televised cabinet meeting that lasted more than three hours on Tuesday, the US president defended his move to fire Fed governor Lisa Cook on Monday evening, adding that he looked forward to having “a majority very shortly” on the central bank’s board of governors.

However, Trump’s attempt to force Cook out over allegations of mortgage fraud — presented by his ally and frequent Fed critic Bill Pulte — has already hit the first in what is likely to prove one of several legal hurdles in a case that could have a profound impact on the Fed’s independence.