It would certainly be legal for the former Arkansas governor to announce his decision if he were being interviewed on a Fox News show, said Ryan, because that falls under the media exemption for in-kind contributions. The difference in this case is Huckabee would be making the announcement on his own show, presumably where he retains full editorial control.
Complicating the legal picture is the fact that Huckabee's situation is rare - very few prospective presidential candidates have had their own TV shows. Ryan said he isn't aware of the situation ever occurring before.
"Candidates and their employers have for decades steered clear of these landmines," Ryan said.
Regardless, the potential legal fallout raises the question of why Huckabee and Fox would take the risk at all. Using his show to reveal his decision won't help him receive any additional media coverage - the former governor's announcement would have been heavily covered whatever the venue.
"It would be unwise in my view to push the boundaries here for what appears to be insubstantial gains," said Ryan. "You risk launching your campaign with a campaign finance scandal."
Fox News was not immediately available to comment.