If Trump knew that Cohen was advancing him a $130,000 loan for campaign purposes, that would have to be reported by the campaign, as would the payments Giuliani said Trump made in installments to Cohen. These would be campaign expenditures that the committee has to keep track of. As Philip Bump notes, if the Trump Organization facilities were used to help make these payments, then there may be additional campaign violations related to the use of corporate resources for campaigns.
Although many campaign finance violations are handled just as fines, as Giuliani seemed to suggest in his Hannity interview Wednesday night, that’s not true for willful violations of campaign finance law, especially those implicating the public interest. Those can lead to criminal liability. If there was an unreported six-figure loan to the campaign to pay off someone who had an affair with a presidential candidate, with repayments facilitated through corporate resources, that seems like a serious enough violation to merit review by the Justice Department.
Ultimately, Giuliani offered two defenses for Trump on Hannity. One, as mentioned, is that the payments were not campaign-related.
The other is that Trump did not know the specifics of what Cohen was doing; just that Cohen was the fixer taking care of things just like Giuliani said he did for his clients. It is a defense that could well be corroborated or rejected based on what’s in the seized Cohen materials.