At best, the underlying criminal act is a violation of campaign finance law, and given the current dysfunctional nature of the Federal Elections Commission mitigates against even that.
That being said, in this sort of situation, it’s frequently not the crime, it’s the coverup, and when the FBI executes a predawn raid on one of the principals in the matter, it’s starting to get really interesting:
FBI agents raided the home in Alexandria, Va., of President Trump’s former campaign chairman, arriving in the pre-dawn hours late last month and seizing documents and other materials related to the special counsel investigation of Russian meddling in the 2016 election.
The raid, which occurred without warning on July 26, signaled an aggressive new approach by special counsel Robert S. Mueller III and his team in dealing with a key figure in the Russia inquiry. Manafort has been under increasing pressure as the Mueller team looked into his personal finances and his professional career as a highly paid foreign political consultant.
Using a search warrant, agents appeared the day Manafort was scheduled to testify before the Senate Judiciary Committee and a day after he met voluntarily with Senate Intelligence Committee staff members.
The search warrant requested documents related to tax, banking and other matters. People familiar with the search said agents departed the Manafort residence with a trove of material, including binders prepared ahead of Manafort’s congressional testimony.
Investigators in the Russia inquiry have previously sought documents with subpoenas, which are less intrusive and confrontational than a search warrant. With a warrant, agents can inspect a physical location and seize any useful information. To get a judge to sign off on a search warrant, prosecutors must show that there is probable cause that a crime has been committed
This must have rattled their cages.