Under the sentencing guidelines cited in the plea agreement, Mr. Cohen faces a maximum of between five and six years in prison for income tax evasion, false statements to a financial institution and campaign finance violations. His sentencing is scheduled for Dec. 12.
Mr. Mueller’s office originally referred his case to federal prosecutors in New York, apparently because the allegations against the president’s longtime fixer fell outside the special counsel’s mandate. But if Mr. Cohen provides substantial assistance to the Russia investigation or any criminal inquiry, prosecutors might agree to tell the sentencing judge that he deserves a lighter punishment.
Mr. Cohen admitted in court that during the campaign, Mr. Trump directed him to arrange payments to an adult film actress and a former Playboy model to keep them from speaking publicly about their affairs with him. The payments violated campaign finance laws that govern corporate and personal contributions.
One payment was to Stephanie Clifford, the pornographic film actress better known as Stormy Daniels, who was given $130,000 in the run-up to the 2016 presidential election. Prosecutors said that to reimburse Mr. Cohen for the payment, executives from the Trump Organization allowed him to file false invoices that listed it as a legal expense.
The arrangements for the other payment, to Karen McDougal, the former Playboy model, were more complex, and involved a tabloid buying the rights to her story and then killing it.
Mr. Cohen turned against the president only after months of pressure from federal authorities, who were investigating Mr. Cohen’s businesses and his financial dealings with banks and tax authorities. His guilty plea infuriated Mr. Trump, who said giving information to prosecutors in return for lesser charges “almost ought to be outlawed.”
His questioning comes during a spurt of activity from the special counsel’s office. Besides securing Mr. Manafort’s guilty plea to conspiracy charges and agreement to cooperate with their investigation, prosecutors wound up a case against George Papadopoulos, a former Trump campaign aide who was sentenced this month to 14 days in prison for lying to federal authorities.
They also asked to schedule the sentencing of Michael T. Flynn, Mr. Trump’s former national security adviser, for late this year.