Reacting to scrutiny of the more than $1 million it has accepted from federal contractors, a super PAC supporting Mitt Romney is now advising donors who do government work to seek legal advice before giving.

In language added to its website this week, the Restore Our Future political action committee said: "Federal government contractors should consult counsel prior to making a contribution."

The new text appeared within days of an Inquirer report that the PAC had solicited donations from at least eight companies with federal contracts, despite a decades-old ban prohibiting such contractors from making political donations.

The added language does not go as far as the warnings already on websites for PACs such as the Obama-backing Priorities USA Action and the Karl Rove-managed American Crossroads. Both require donors to certify they are not government contractors before their donations are processed.

"It would have helped if they would have told us that earlier," said a representative from one of the contractors that donated to Restore Our Future. He spoke on the condition of anonymity and said he and his employer were unaware of the contractor ban when the PAC solicited the contribution last year.

A spokeswoman for Restore Our Future declined to answer a reporter's questions Wednesday on when or why the new language was added to the site.

Congress first banned federal contractors from donating to political groups as part of the 1939 Hatch Act, but for years that prohibition has been overshadowed by other restrictions that prevented all corporations from giving.

But the law has attracted new attention in the wake of 2010 Supreme Court decision in the Citizens United case, which equated corporate campaign contributions with free speech and opened the doors for businesses to give as much as they like to independent groups.

Super PACs can now collect and spend unlimited sums from corporations, unions, and individuals, provided they do not coordinate directly with a candidate or a campaign.

In their landmark ruling, the justices made no specific mention of the 1939 ban on federal contractor giving - a law enacted to discourage businesses from buying their way into contracts and politicians from dangling the promise of government work to extort campaign cash from businesses.

The omission led many firms that donated to Restore Our Future to conclude that the Citizens United decision nullified the contractor ban.

In an interview Wednesday, at least one leading campaign-finance expert reversed his earlier opinion on the viability of that argument.

In The Inquirer article Tuesday, Kenneth A. Gross, a former general counsel for the Federal Elections Commission, agreed with those firms understanding of the law.

On Wednesday, he said that, in fact, the FEC has already ruled on this question, upholding the ban.

In a little-noticed 2011 decision centered on contractor donations to a PAC called Alaskans Standing Together, the commissioners found that contractors remain "prohibited from making contributions toward any political party, committee or candidate for public office or to any person for any political purpose or use."

"The more I look at it, the more I have to take the position that it is impermissible for a super PAC to accept federal contractor money," Gross said Wednesday.

Contact Jeremy Roebuck

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