ST. PAUL — Minnesota campaign regulators reinforced a wall of separation between candidates and outside political groups Tuesday, issuing an opinion that discourages them from cooperating on fundraising that could eventually pour money back into the politicians’ races and likely violate state law.

The Campaign Finance and Public Disclosure Board, in the opinion adopted unanimously, determined that such activity would destroy the legal independence of the political groups and give candidates an invitation to solicit “disguised contributions” they aren’t allowed to put into their own coffers. The groups face fewer restrictions in the amounts they raise and where the money comes from, including the ability to accept corporate donations that cannot be made to candidates.

The guidance comes during an election year when the influence of well-financed groups that flood targeted races with mailings and TV ads comes into play, which sometimes surpasses the candidates’ spending. Groups are already stocking up for a fall battle for control of the Minnesota House and a bigger prize: the governor’s office.

Independent expenditure groups can argue for the election or defeat of candidates as long as they don’t act in concert with candidates. The board’s opinion doesn’t affect the ability of candidates to help established political parties raise money; they are also barred from taking direct corporate cash.

Board member George Beck said the ruling maintains the “highest degree of separation” possible between candidates and the affected groups. Board opinions are technically nonbinding, but they often provide a road map for future campaign activity and guide investigations when complaints arise.

Regulators were responding to a request from David Asp, the Minneapolis attorney for a candidate who was approached about raising money for an unidentified independent group. Asp wouldn’t publicly identify the candidate, but an adviser to Republican gubernatorial candidate Jeff Johnson confirmed to The Associated Press the request came on behalf of his campaign.

In correspondence and testimony before the board, Asp said the opinion encroaches on free speech and could draw lawsuits. He said the functions of raising money and crafting a message for voters are separate and could be kept that way.

The lawyer said using a candidate’s fundraising assistance as a trigger to outlaw a group’s subsequent participation in a race “will be pushing the limits of First Amendment protection for candidates, committees and parties.”

Gary Goldsmith, the board’s executive director, said he couldn’t recall the six-member panel ever being sued over an advisory opinion, but he cautioned members that it could happen here. He added that he was confident the opinion is on sound legal footing.

“Nobody is going to be limited in the amount of independent spending they can do,” Goldsmith said, adding that candidates are free to speak on whatever issue they wish. “Cooperation is the issue here.”

Gregg Peppin, the adviser to Johnson, said the campaign was seeking sincere clarification about what would pass muster. He wouldn’t identify the group that wanted to collaborate, but said Johnson won’t test the board’s limitation on cooperation.

“Our goal is to play by the rules and they have ruled that’s not permitted,” Peppin said. “And that’s the rule we’ll be following.”

While confined to races for Minnesota government office, the board’s consideration of the request drew wider notice. The Washington-based Campaign Legal Center weighed in this week with a lengthy letter supportive of the action ultimately taken.

“Placing reasonable limits on the degree of cooperation that may occur between a candidate and a purportedly ‘independent’ group represents a practical and perfectly legal approach to the question at hand,” the center’s executive director, J. Gerald Hebert, wrote.