Asked by TPM before a Senate vote on Tuesday to clarify whether he worked out the agreement before or after his 2010 campaign, Johnson did not give a direct answer.
"It's a private company," he said. "We fully complied, fully disclosed [and] followed the law, complied with the spirit and letter of the law, and again it's a private company. Those financial matters end up being more complex."
Pressed again on the specific question of timing, Johnson walked away to vote.
Johnson's office also ignored multiple questions about the windfall payment on Monday. He has yet to produce a written deferred compensation agreement that was signed and dated before he launched his campaign. Election law attorneys say a written agreement is critical, and without one, Johnson could face serious charges that he violated campaign-finance laws barring direct corporate funding of federal candidates.
"It depends on whose money it was," Arent Fox's Brett Kappel told TPM. "If there was a deferred compensation agreement before he ran for office, that would be a legitimate corporate payment [to him personally]. If there was no deferred compensation agreement at all, and the company is paying for his campaign, that would be a problem."
In fact, because Pacur is a private company, the Federal Election Commission could target him personally for cutting himself a potentially illegal corporate check. The Justice Department could also take up the case for violations of the Federal Election Campaign Act.
"If he's the officer...he would have personal liability [for cutting the checks to his campaign from the corporate coffers]," Kappel added. "The FEC has historically gone after the officers of the company in these cases. He would be liable not as a candidate, but as a former corporate officer."
When Johnson, a Tea Party favorite, was first asked about the $10 million payment by the Milwaukee Journal-Sentinel last week, he gave a similarly testy response.
"You take a look in terms of what would be a reasonable compensation package, OK?" Johnson told the Journal-Sentinel last week. "It's a private business. I've complied with all the disclosure laws, and I don't have to explain it any further to someone like you."