Just as the Senate Rules and Administration Committee announced Friday that it would mark up a bill this week requiring Senate candidates to file their campaign reports to the Federal Election Commission electronically, the ranking member of the committee began circulating an amendment that some government watchdog groups are calling a “poison pill” that will doom the bill.

Sen. Bob Bennett (R-Utah) wants to attach an amendment to the electronic disclosure bill that would lift the caps on coordinating spending between party campaign committees and individual campaigns.

Bennett and Senate Minority Leader Mitch McConnell (R-Ky.) say that is not a controversial idea. Both contend the amendment would shed more light into the financing of campaigns.

“Sen. Bennett believes this amendment is needed to inject more transparency and accountability into federal elections,” Bennett spokeswoman Emily Christensen said. “By lifting the coordinated spending limits, parties and candidates will have to stand behind their campaign ads. This should be noncontroversial, and the Senator believes Congress should act now before we get too far into the 2008 election cycle.”

But some government watchdog groups warn that any amendment to the disclosure measure could scuttle the bill, which is sponsored by Sens. Russ Feingold (D-Wis.) and Thad Cochran (R-Miss.) — just as it is making its first real progress since Feingold initially introduced it in 2003.

“A vote for such an amendment would be a vote to assure that, despite its broad Senate and public support, Senate electronic disclosure will not come to the Senate floor and will not pass Congress,” Michael Malbin, executive director of the Campaign Finance Institute, wrote Friday in a letter to all Rules Committee members.

At a March 14 hearing on the legislation, Rules Chairwoman Dianne Feinstein (D-Calif.) cautioned against controversial amendments.

“I wanted to build the case for urging my colleagues to refrain from holding this bill hostage over the campaign finance battles that have been going on for years,” she said.

Feinstein added that “looking at the difficult path that this legislation has had … it was important that this committee establish a legislative record which … will demonstrate the strong support that is out there for electronic filing.”

The FEC has long supported making Senate candidates file their campaign finance reports electronically, just as House and presidential candidates and federal political action committees do.

But McConnell spokesman Don Stewart said the Minority Leader — a frequent opponent of campaign finance reform measures — supports Bennett’s amendment and does not think it will affect the push to make Senate candidates file electronically. He said the amendment “makes the committees accountable for the ads” they pay for through independent expenditures.

Stewart cited the controversial TV commercial created by the independent expenditure arm of the Republican National Committee that ran in Tennessee last cycle, implying that then-Rep. Harold Ford Jr. (D-Tenn.) was a ladies man.

Even though many civil rights groups and politicians from both political parties found the ad offensive, Stewart said no one could yank it from the airwaves because the RNC was not allowed to talk to the entity that made it.

If Bennett’s amendment became law, there would be no need for the party committees to establish separate, independent groups, he said.

Cochran is not likely to support Bennett’s effort.

“Certainly Sen. Cochran, as far as amendments go, wants to make sure that nothing is added that would hinder the expeditious passage of the bill,” Cochran spokeswoman Margaret Wicker said. “It’s been so long in coming, he just wants to make sure the committee will report it out in a form that hopefully the Senate would approve by unanimous consent.”

Wicker added that Cochran “will defend the bill in its [current] form in the markup.”

Cochran, who sits on the committee, and Bennett, the ranking member, have not spoken yet, Wicker said late Friday. However, Cochran “certainly will do whatever he thinks is necessary to get the bill approved,” she said.

The Feingold-Cochran measure simply requires Senate candidates to file campaign reports electronically with the FEC.

Currently, they file paper copies with the Secretary of the Senate, who then must scan all the pages and transmit them to the FEC. The FEC then has to enter much of the information manually before posting the reports online.

That causes delays, makes it harder for the public to find or see the reports and is costly.

Feinstein said it costs taxpayers $250,000 annually.

The bill has 30 co-sponsors and no one has spoken against the measure.

Howard Gantman, Feinstein’s staff director on the Rules Committee, said any changes beyond a technical one Cochran and Feingold have signed off on that would push back the bill’s enactment date, could doom it.

“The best way to pass this on the floor would be as a stand-alone bill,” Gantman said. “If Members were successful at getting an amendment in committee, that would spark a lot of controversy … that would virtually kill it.”

Some advocates of electronic filing believe that McConnell does not actually support the idea. They point to his vigorous efforts against the Bipartisan Campaign Reform Act and his pursuit of litigation stemming from that landmark bill.

Others note that Bennett and McConnell are very close.

Stewart dismissed the idea as inaccurate conspiracy theories.

“He does not object to electronic filing,” Stewart said. “Sen. McConnell has been a proponent of this fix for some time.”

Stewart added that McConnell does not now, nor has he ever had, a hold on the bill.

Supporters of Bennett’s amendment have noted that the Campaign Finance Institute supports the amendment.

But Steve Weissman, associate director for policy with the institute, said that is not quite right.

Malbin, the group’s executive director, personally supports lifting the caps but “is opposed to putting it on this bill because he knows that it would make it controversial and kill it,” Weissman said.

Democrats are not likely to go along with Bennett’s idea.

Senate Majority Leader Harry Reid (D-Nev.) opposes the amendment.

“We support a clean bill,” said Reid spokesman Rodell Mollineau.