Donald Trump will become the first former president in US history to stand trial on criminal charges when jury selection begins in a New York case that stems from payments made to an adult film actress before the 2016 election.
Trump, 77, is set for an election rematch with incumbent President Joe Biden in November, is charged with 34 counts of falsifying business records as part of a scheme involving his former lawyer Michael Cohen to conceal the $US130,000 ($A200,000) pay-off made to Stormy Daniels.
Daniels said the money was given to keep her quiet about an affair she had with Trump in 2006.
He has admitted paying her on the eve of the 2016 election to stop her "false and extortionist accusations" but denies any sexual encounter.
Trump's lawyers made several unsuccessful attempts to have the hush money trial delayed, a tactic they have also used in the former president's three other ongoing criminal cases.
Two of the other cases concern his attempts to overturn his 2020 election defeat and one involves his retention of classified documents after leaving office in 2021.
The process of selecting a jury in New York, a heavily Democratic city, could take several days.
Jury selection begins on Monday and the whole trial before Justice Juan Merchan - in which Cohen and Daniels, whose real name is Stephanie Clifford, are expected to testify - could last up to eight weeks.
Trump, who has pleaded not guilty, faces a maximum of four years behind bars if convicted.
Trump told reporters on Friday he was ready to take the stand to defend himself, although it is far from certain the Republican real estate tycoon would actually undertake such a risky legal strategy.
In any case, Trump's campaign for the presidency will collide with his courtroom obligations as he is required to be present every day of the historic trial.
Trump's legal entanglements are extensive.
The most serious are his four criminal indictments in four different cities.
Besides the New York case, two involve his alleged efforts to keep himself in power after Biden defeated him in 2020 and another concerns the retention of classified documents after leaving office.
The three other trials do not yet have firm start dates.
Already in 2024 Trump has been dealt major blows in two New York civil lawsuits, one accusing him and his organisation of committing fraud and another for defaming magazine columnist E Jean Carroll when he denied her claims of sexual assault.
Trump owes more than $US500 million in legal penalties in the combined cases.
Trump claims, without evidence, he is a victim of political persecution orchestrated by Democrats to keep him from the White House.
Even if he is convicted, the US Constitution does not prevent a felon running for the presidency.
Trump and Biden remain locked in a neck-and-neck race, according to an opinion poll from the New York Times and Siena College, with Trump holding a 46 per cent to 45 per cent edge over Biden.
