President Donald Trump is wielding a new tool in his fight against political and policy foes: alleging mortgage fraud.

New York Attorney General Letitia James on Thursday was indicted on charges of alleged bank fraud and making false statements to a financial institution regarding a mortgage loan.

That followed Trump's allegation that Federal Reserve Governor Lisa Cook lied on a mortgage application, which he is using as grounds for attempting to fire her. Meanwhile, the Democrat who led Trump's first impeachment trial, Senator Adam Schiff, is now under criminal investigation for similar accusations.

But this type of offence is rare, and it can be difficult to prove malicious intent.

That, in turn, may hurt federal prosecutors' ability to meet Trump's desire, as expressed in a recent social media post directed at Attorney General Pam Bondi, to win legal cases against James and Schiff, quickly.