Washington: As Donald Trump prepares to mount a legal defence in the first criminal trial a former or sitting American president has ever faced, it is not clear who will foot the legal bills: the former president or his political donors.

Last year, he spent roughly $US10 million ($14.7 million) from his political action committee (PAC) fund, Save America, on his own legal fees, federal election filings show. Trump, the front-runner in the early days of the campaign for the 2024 Republican presidential nomination, was arraigned in Manhattan on 34 felony charges on Tuesday (Wednesday AEST). He pleaded not guilty.

It was not immediately known whether he might set up a separate legal defence fund to cover the expenses associated with the case in New York, which stems from hush money payments to a porn actress in the waning days of the 2016 election that catapulted him to the presidency.

Those federal election filings also showed that Trump’s PAC paid more than $US16 million overall in legal-related expenses to various law firms and lawyers in 2021 and 2022, including those directly related to Trump as well as for lawyers representing witnesses in investigations he is facing.

The payments have drawn scrutiny from some campaign finance experts, who have questioned whether Trump, as a candidate, can continue to use the PAC to pay for his personal legal bills and circumvent rules for traditional candidate committees.

At the same time, sceptics say that Trump is operating in a grey area, particularly if he is charged with a campaign finance violation in connection with concealing a payment to Stormy Daniels to ensure she did not go public with her story of a sexual liaison with Trump.

Trump’s lawyers could argue that those legal expenses are campaign-related, said Richard Hasen, a law professor and political science at UCLA and an election law expert.

“In these campaign finance cases, if it’s murky, some campaign lawyers see that as a green light,” he said.