Asked what questions might be appropriate, the lawyer Rudy Giuliani, a former New York mayor, suggested two to Reuters: “Was there some agreement with the Russians? Was there any meeting of Trump with the Russians?”

A former federal prosecutor, Giuliani said he was the president’s new chief counsel in the Russia investigation but that he would also keep an eye on a U.S. inquiry into a $130,000 hush payment by longtime Trump attorney Michael Cohen to a porn star who said she had a 2006 sexual encounter with Trump.

Giuliani said he wanted any Trump interview with Mueller to be limited in time and scope, suggesting for only 2-1/2 hours and not under oath.

In addition to the Russia questions, Giuliani said investigators could ask about possible obstruction of justice related to Trump’s firing a year ago of then-FBI Director James Comey.

The two sides have been negotiating the terms of a possible interview for months, including topics Mueller might pursue as part of a nearly year-old inquiry into possible collusion between Moscow and Trump’s presidential campaign.

The Kremlin has denied assertions by U.S. intelligence agencies that it meddled in the election. Trump has denied any collusion and has described the investigation as a political witch hunt.

Giuliani, who joined Trump’s legal team last month, said they were trying to figure out whether it was a good idea for Trump to voluntarily submit to an interview.

“Are they trying to trap him?” Giuliani asked. He said Trump’s legal team expected to make a decision in two or three weeks. “We want to get it over with,” he said.

Giuliani said Trump had used retainer fees starting in 2017 to reimburse Cohen for the $130,000 Cohen paid the porn star, Stormy Daniels, in the closing weeks of the November 2016 election.

Trump wrote in a tweet on Thursday that Cohen was not paid using campaign funds. The payment was part of a “private agreement” that involved money that had “nothing to do with the campaign,” Trump said.

He said the payment was aimed at stopping “false and extortionist accusations” Daniels made about a sexual encounter with Trump. Trump acknowledged a non-disclosure agreement with her to secure her silence. He denied they had an affair.

The president had previously told reporters he did not know about the payment Cohen made to Daniels.

The investigation of Cohen is an offshoot of Mueller’s probe.

The claim of repayment is significant because a payment by Cohen could be seen as an illegal campaign contribution. Trump as candidate would have been permitted to make unlimited personal contributions to his own campaign.

But several experts pointed out an undisclosed campaign loan is also a violation of federal election law.

    “It is hardly an improvement to claim that what was claimed as a gift is now a secret loan from your lawyer to pay hush money to a porn star,” said Jonathan Turley, a George Washington University Law School Professor who has frequently expressed skepticism about the legal case against the president.

But legal watchdog group Citizens for Responsibility and Ethics in Washington (CREW) said it was asking the Department of Justice and Office of Government Ethics to investigate whether Trump made an illegal false statement by not including the $130,000 payment in his personal financial disclosures.

The group said Trump was legally required to disclose any liability in excess of $10,000.

Other legal experts said the payment may not qualify as the sort of financial obligation Trump would have been required to disclose.

Peter Henning, a law professor at Wayne State University, said that while prosecutions for making false statements to the government are common, they are rarely based on an omission on a financial disclosure form.

“I don’t see this becoming a case,” he said.

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