Donald Trump claims he will be arrested on Tuesday on charges stemming from an investigation into a $130,000 payment to porn star Stormy Daniels in 2016.
If he is, he would be the first former president to face criminal charges.
Here are some key questions on the issues at play in this case.
What is Trump accused of?
In 2016, adult film star Stormy Daniels contacted media outlets offering to sell her account of what she said was an adulterous affair she had with Donald Trump in 2006.
Mr Trump's team got wind of this, and his lawyer Michael Cohen paid $130,000 to Ms Daniels to keep quiet.
This is not illegal. However, when Mr Trump reimbursed Mr Cohen, the record for the payment says it was for legal fees. Prosecutors say this amounts to Mr Trump falsifying business records, which is a misdemeanour - a criminal offence - in New York.
Prosecutors could also potentially allege that this breaks election law, because his attempt to hide his payments to Ms Daniels were motivated by not wanting voters to know he had an affair with her. Covering up a crime by falsifying records would be a felony, which is a more serious charge.
Even advocates for prosecution acknowledge that either way, this is by no means a clear-cut case. There is little precedent for such a prosecution, and past attempts to charge politicians with crossing the line between campaign finance and personal spending have ended in failure.
"It's going to be tough," says Catherine Christian, a former financial prosecutor for the New York City district attorney.