Donald Trump is hiding in Florida ahead of his arrest this week on allegations stemming from an investigation into a $130,000 (£106,000) payment to porn star Stormy Daniels in 2016.
He will be the first US president to face criminal charges.
Here are some important questions about the issues at play in this case.
Why is Trump accused?
In 2016, porn star Stormy Daniels contacted the media to sell her account of what she said were adulterous affairs she had with Donald Trump in 2006.
Mr Trump’s team received the information, and his lawyer Michael Cohen paid Ms Daniels $130,000 as a way to silence her.
This is not illegal. However, when Mr. Trump returned to Mr. Cohen the record of the payment showed that it was a legal payment.
Prosecutors say this amounts to Mr Trump falsifying business records, which is a misdemeanor – a felony – in New York.
Prosecutors may also argue that this violates election law, because his attempt to hide his payments to Ms. Daniels was motivated by not wanting voters to know he was having an affair with her.
Concealing a crime by falsifying a record would be a felony, which is a more serious charge.
Even the prosecution lawyers agree that in any case, this is not a clear cut case.
There is little precedent for such prosecutions, and previous attempts to prosecute politicians for crossing the line between campaign finance and personal spending have ended in failure.
“It’s going to be a tough case,” says Catherine Christian, a former New York City district attorney’s prosecutor.
Will he really be charged?
The decision on whether to file charges is up to New York District Attorney Alvin Bragg.
He set up a grand jury to investigate whether there was enough evidence to file charges, and only he knows if – or when – an indictment will be announced.
Last week, Mr Trump’s lawyers said the former president had been given a chance to appear before the supreme court, which is seen as a sign that the investigation is nearing completion.
His lawyers have dismissed suggestions that they or Mr Trump have any advance notice of the impeachment, saying his comments on Tuesday were based on media reports.
However, there are other signs that the panel is wrapping up its investigation.
Both Michael Cohen and his former legal adviser Robert Costello – who tried to discredit Cohen’s testimony – have testified in recent days.
And it is unclear whether the grand jury will hear from any other witnesses.
After Wednesday’s scheduled hearing was unexpectedly canceled, the waiting game for a decision continues.
What will happen if Trump is impeached?
If Mr. Bragg decides to proceed with the charges, he will first inform Mr. Trump and his lawyers, and start a conversation about how and when the former president will arrive in New York City for official arrest and the first hearing of the case in court.
The formal indictment against Mr Trump will not be made public until a judge reads the charges against him.
Given the historic nature of the move, and security concerns, the details of Mr Trump’s New York appearance are uncertain.
Mr Trump’s lawyers have indicated that he will cooperate with New York authorities, so there will be no warrant for his arrest.
Mr Trump has his own private jet, so he can arrive at one of several New York airports and then travel to lower Manhattan by car.
If Trump is arrested, will his fingerprints be taken?
As part of the negotiations with prosecutors, the court may also agree to give him a private area to enter the courtroom, instead of the more usual “walk” in front of the assembled media.
Once inside, however, Mr Trump will be fingerprinted and photographed like all criminal defendants.
He will also be read his rights, remind him of his constitutionally protected right to counsel and refuse to talk to the police.
Criminal defendants are usually held in handcuffs for a period of time, although Mr Trump’s lawyers will try to avoid that for their client.
Throughout the appointment process, he will be accompanied by Secret Service agents.
Mr Trump will then wait in a detention area or cell until he is brought before a judge. The arraignment – the time when the accused makes his plea before the judge – is open to the public.
When the trial is scheduled, a judge will be selected, other details will be provided, such as the duration of the trial and possible travel restrictions and bail conditions for the defendant.
A misdemeanor conviction can result in a fine.
If Mr Trump is convicted of the felony charge, he faces a maximum of four years in prison, although some legal experts predict that a fine is more likely, and that he is unlikely to face any jail time.
Can he still run for president?
Impeachment or even a criminal conviction will not stop Mr Trump from continuing his presidential campaign if he chooses to do so – and he has given every indication that he will continue to press forward no matter what.
The truth is, there is nothing in US law that prevents a candidate convicted of a crime from campaigning, and becoming president – even while in prison.
“However, Trump’s arrest will undoubtedly complicate his presidential campaign.”
While it may cause some Republican voters to rally around their champion as a way to support him, it can be a huge nuisance for a candidate on the campaign trail, trying to get votes and participate in debates.
It could also add to and fuel the already sharp divisions within the American political system.
Conservatives believe the former president is held to a different standard of justice, while liberals see this as a matter of holding lawbreakers accountable – even those in the highest positions of power.