WASHINGTON _ New Hampshire’s controversial push poll law may be on shaky legal ground when it comes to candidates for federal offices.

A member of the Federal Election Commission said Thursday the state cannot force federal candidates to identify themselves to voters when they conduct polling calls calls against their opponents.

The Federal Election Campaign Act, which requires no such disclaimer on polling calls, “clearly preempts” the state push poll law for federal elections, Commissioner Donald McGahn said during a meeting of the six-member Federal Election Commission.

“This isn’t about federalism,” said McGahn. “It’s different. It’s about federal elections, and the Constitution makes clear that the House and Senate are the judge of their elections and they are the ones who can pass laws.”

Lawyers for Democratic pollster Greenberg Quinlan Rosner Research, which intends to conduct polling for federal candidates and nonprofit special interest groups in New Hampshire this election year, have asked the FEC for an advisory opinion on whether the state statute regulating push polls is superseded by federal law.

Greenberg Quinlan attorney Joseph Sandler told the commission the matter may ultimately be decided in the courts, but he said an advisory opinion favorable to his client’s view by the FEC would be recognized by the New Hampshire Attorney General’s Office “and may obviate the need for litigating the matter.” He said the federal courts have often upheld the FEC on preemption questions.

“Congress has made clear that this issue is not to be decided by the State of New Hampshire,” Sandler said. “It’s to be decided by Congress, as interpreted by this commission.”

Pollsters working on both sides of the political aisle have expressed frustration with the law’s requirement that a call designed to give voters negative information about an opposing candidate under the guise of a poll must identify “by name” the candidate the call is supporting.

They say the law makes it difficult, if not impossible, to conduct message testing surveys, which are different than push polls, without fear of being threatened with legal action by the New Hampshire Attorney General’s Office.

Pollsters have also been upset by the state Attorney General’s Office recent stepped-up enforcement of the law.

Last week, the Attorney General’s Office filed a civil suit in state court against U.S. Rep. Charlie Bass’s campaign, charging that it “deliberately” avoided following the push poll law by substituting the National Republican Congressional Committee for the Bass campaign in a disclaimer on a push poll against Democratic challenger Ann McLane Kuster in 2010.

The Bass campaign said the survey in question was “legitimate message testing,” not a push poll.

The suit against Bass marked the fourth time in 18 months the attorney general has reached settlements or initiated civil enforcement actions related to election laws on push polling and so-called “robo” calls.

The FEC originally considered issuing an advisory opinion on Thursday, but decided to only discuss the issue and put off further action until its next meeting on April 26.

While there is no dispute that the state law applies to candidates for state offices such as governor and the state Legislature, the question is whether it can apply to candidates for federal offices.

Greenberg Quinlan also wants to know if the federal law preempts the state law regarding telephone surveys made on behalf of nonprofit organizations that refer to candidates for federal office, but do not expressly advocate their election or defeat.

Four potential advisory opinions have been drafted. One says the federal law preempts the state law as applied to both federal elections and nonprofits.

A second draft says federal law preempts the state law as applied to federal candidates but not calls for nonprofits.

A third draft says that although the federal law “likely” preempts the state law, it is up to the courts, not the FEC to make the call.

In a fourth draft,the FEC declines to give its opinion because it says the question is not within its jurisdiction.

McGahn and commission Chair Caroline Hunter, both appointees of Republican former President George W. Bush, agreed the commission should issue the draft that says the federal law preempts the state law with respect to both candidates and nonprofits.

But McGahn was the only commissioner to comment at length during Thursday’s meeting.

The federal campaign law regulates expenditures by federal candidates and requires disclaimers for traditional advertising. But the Attorney General’s Office argues the state push poll law “is a direct regulation of a transaction outside the area of campaign expenditures.”

In written comments to the FEC, the attorney general said, “New Hampshire’s disclaimer requirement does not prevent or impede the ability of a federal candidate to pay for a telephone survey. The existence of a disclaimer and the payment for the survey where that disclaimer is required are two distinct transactions.”

McGahn said the attorney general’s argument helped him make up his mind _ that the attorney general is wrong.

“It convinced me that (federal law) clearly preempts” the state law,” he said.

“What I don’t understand about the law is, what if it is an independent expenditure” by a group unconnected with the candidate?” said McGahn. “Is this saying you have to put in a disclaimer on the call to make it sound like it’s in support of a candidate?”

McGahn said the attorney general’s argument “loses all credibility” when it said that the state’s ability to limit expenditures by federal candidates “might arguably be preempted” by federal law. He said it is not arguable at all and to say it is “gives away what’s at stake here.”