New Jersey Gov. Chris Christie may manage to put the George Washington Bridge scandal behind him, but even if he does, his ethics troubles won’t be over.  

Christie’s complicated relationship with campaign contributors and state contractors, in particular, will draw scrutiny as he continues to mull a 2016 presidential bid. Christie’s donors have a history of gravitating to secretive and little-regulated political groups to promote the GOP governor and his agenda.  

These include tax-exempt organizations that spent millions on Christie’s gubernatorial election and re-election campaigns, and that operate outside the disclosure rules. Political activity by nonprofits has become commonplace these days, and Christie’s opponents run their own non-disclosing tax exempt groups.  

But Christie’s big backers, who have bankrolled several pro-Christie operations, stand out because many of them are state contractors otherwise barred from contributing to his campaign. New Jersey “pay-to-play” laws, considered the strictest in the nation, bar large state contractors, utilities and financial services firms that manage state pension funds from donating to state candidates.  

Yet a long list of New Jersey contractors and pension fund managers have given generously to groups that either back or are closely linked with Christie. Such contributions have repeatedly raised questions as to whether Christie supporters are skirting the state’s pay-to-play laws — a suggestion that the state Treasury Department, which enforces those statutes, has rejected.  

The Republican Governors Association, which has raised $18 million since Christie assumed its chairmanship in November, has a long list of donors from businesses that hold millions worth of government contracts with the Garden State, according to the New Jersey Bergen Record. In the months leading up to Christie’s chairmanship, when he was serving as vice chairman, the RGA raised more than a half-million dollars from New Jersey utilities, individuals and businesses with significant state contracts, The New York Times reported.  

“Government contractors cannot make contributions directly to Christie, but what they can do is give contributions to the RGA,” said Craig Holman, government affairs lobbyist for Public Citizen. “And the RGA can use those contributions to promote Christie.”  

The RGA spent some $1.7 million to help re-elect Christie in 2013. Asked about donations from New Jersey contractors, RGA spokesman Jon Thompson said the organization “raises funds to elect and support Republican governors, and we do that in compliance with all laws.” A spokesman for the New Jersey Treasury Department said the RGA donations from state contractors present “no conflict of interest” and that every contract is “reviewed and scrutinized prior to approval.”  

But the state’s pay-to-play statute has “a very strong anti-circumvention clause,” noted Heather Taylor, a spokeswoman at the New Jersey Citizens Campaign, a civic education group that helped draft the rules. The clause bars contractor contributions made through third parties, including consultants and lawyers. The RGA’s money from state contractors “warrants further review,” Taylor said.  

It’s not the first time an organization associated with Christie has enjoyed state contractors’ largesse. Contractors were among the top donors  in 2009 to a pro-Christie tax-exempt group known as Reform Jersey Now, Jersey news outlets reported at the time. The group spent close to $624,000 on direct mail and radio ads to tout Christie’s proposed cap on property taxes, but disbanded soon after releasing its donor list under pressure from Democratic legislators.  

Christie campaign contributor and New Jersey biotech executive John Crowley had given Reform Jersey Now $25,000. Another Christie donor, Mark Gerson, co-founder of a New York brokerage firm, had also kicked in $25,000. Other $25,000 donors included construction, engineering and law firms with large state contracts. The group’s advisory board was stacked with Christie confidantes, including New Jersey lawyer and GOP committeeman Bill Palatucci.  

State contractors have also given generously to the Drumthwacket Foundation, the Huffington Post recently reported . The group helps maintain the governor’s mansion and its budget has soared during the Christie administration. Organizers have said their activities are above board.  

Yet another tax-exempt group, the Committee for Our Children’s Future, spent more than $6 million on pro-Christie ads in the run-up to his 2013 re-election, New York Public Radio reported. That group’s organizers included Bob Teeven and Lynn Grone, who attended the University of Delaware with Christie. Both Reform Jersey Now and the Committee for Our Children’s Future vanished without a trace after running their pro-Christie ads, filing no public records with the IRS.  

When asked about the pro-Christie groups, Christie spokesman Kevin Roberts noted that the labor-backed progressive nonprofit One New Jersey has spent money on anti-Christie attacks, also without disclosing its donors. Roberts referred CQ Roll Call to Christie’s public comments on Reform Jersey Now in 2009: “There are a group of citizens who are out there to advocate policies in line with mine, and that’s great.”  

As with Christie’s more recent troubles, that’s a response that is likely to beg further questions.  

Correction: 1:59 p.m. An earlier version of this post misstated which organization Christie leads. He is chairman of the RGA.