For the first time, prosecutors have tied US President Donald Trump to a federal crime, accusing him of directing illegal hush-money payments to women during his presidential campaign in 2016.

Did Trump commit a crime?
That isn't completely clear. Federal prosecutors didn't accuse Trump in Saturday's court filing of violating the law. However, there was no ambiguity in the court documents that prosecutors believe actions by former Trump lawyer Michael Cohen were criminal and Trump was directly involved. Prosecutors charged that Cohen arranged the secret payments at the height of the 2016 campaign "in coordination with and at the direction of" Trump. They also alleged Cohen made the payment in order to fend off potential damage to Trump's presidential bid. Federal law requires that any payments that are made "for the purpose of influencing" an election must be reported in campaign finance disclosures.

"There is a plausible case against the President," said Rick Hasen, a professor who specialises in election and campaign finance law at the University of California at Irvine. In order to bring charges, prosecutors would have to prove Trump had criminal intent and "willfully violated the law," said Josh Blackman, a professor at South Texas College of Law Houston. Something that would be perfectly legal to do as a businessman could take on a different standard as a candidate and campaign finance laws are "very open-ended," he said.

Hasen said Trump's lawyers could argue Trump didn't have willfulness to break the law if the payments were completely personal and not connected to the campaign, despite their timing.


Can a sitting president be indicted?
Legal experts are divided on that question. The Supreme Court has never ruled on whether a president can be indicted or whether a president can be subpoenaed for testimony. The Justice Department's Office of Legal Counsel, which provides legal advice and guidance to executive branch agencies, has maintained that a sitting president cannot be indicted. Two Justice Department reports, one in 1973 and one in 2000, came to the same conclusion. Those reports essentially concluded that a president's responsibilities are so important that an indictment would pose too many risks for the government to function properly.

Could Trump be indicted once he leaves office?
There would presumably be no bar against charging a president after he leaves the White House. Legal scholars have said that based on the Justice Department's guidance, it would appear that Trump could be charged for wrongdoing during the campaign or as president once he leaves office. The statute of limitations for a campaign finance law violation would be five years.

Could Trump pardon himself?
Courts have never had to answer the question of whether a president can pardon himself. In June, Trump's personal lawyer, Rudy Giuliani told NBC that while Trump "probably does" have the power, "pardoning himself would be unthinkable and probably lead to immediate impeachment".

- AP