The issue is whether there is evidence in emails, or from witnesses, that the $130,000 payment to Daniels just before the 2016 election was made to silence Stormy Daniels because her story could hurt Trump's presidential candidacy.
If Trump lawyer Michael Cohen paid his own money "and he intended it to help the campaign then it's an excessive contribution and it's illegal," Hasen said. Same goes for President Trump's company, the Trump Organization.
If Trump paid out of his own funds, the amount is not an issue because candidates can contribute unlimited money to their campaign. But they have to disclose it, Hasen said, so there could be a disclosure violation.
"This could be construed as a knowing and willful violation of federal election law, in which case it would be a federal crime," said Brett Kappel, a federal election law expert with Akerman LLP.
Experts say there also could be tax implications involving the payment to Daniels, depending on who paid and how it was paid.
