On Tuesday, the House voted 411-to-8 to approve the bill with only 2 Republicans voting against the bill, despite criticism from GOP leaders. In the Senate, Democrats predict they, too, will have the votes to pass the measure because few lawmakers want to go home to explain a vote against a measure whose title is the Honest Leadership and Open Government Act.

Still, House Republican leaders called the bill a "hollow shell of reform" and complained that they had been blocked from any role in drafting final language, which was released Monday.

"The legislation is far from perfect, but the fact that they were able, finally, after all these efforts, to get it together to do this is highly significant," says Norman Ornstein, a senior fellow at the American Enterprise Institute in Washington and a longtime critic of congressional ethics.

The House and Senate have each already voted some version of ethics and lobby reform. In the House, some reforms were adopted as rules, during the first 100 hours of the new Congress. But reformers say it's essential that the new standards be passed as law in both the chambers.

"There was a strong temptation on the part of many to say, 'We've done this, let's move past it,'" says Mr. Ornstein. It's significant that much of the drive to pass a new law came from the former and current chairs of the Democratic Congressional Campaign Committee, Reps. Rahm Emanuel (D) of Illinois and Chris Van Hollen (D) of Maryland, he says.

"What does that tell you? Nobody is closer to the ground [than they are] in understanding what you want your candidates to run on." In the wake of congressional corruption scandals in the last Congress, Democrats knew they needed "a credible case that Congress has cleaned up its act or they couldn't ask voters to send them back," Ornstein adds.

In the run-up to this week's vote, public-interest groups who had rallied behind lobby and ethics reform fell out over whether the reform had gone far enough. A key sticking point is proposed language over how lawmakers will disclose member-sponsored projects, or earmarks.

The legislation requires that earmarks included in bills and conference reports, and their sponsors, be identified on the Internet at least 48 hours before the Senate votes. But the revised bill leaves it to the Senate majority leader or committee chairmen, rather than the Senate parliamentarian, to certify that all earmarks have been identified. The original Senate language allowed members to raise a point of order against individual earmarks on the floor of the Senate. Under the proposed new law, they could raise objections only if the required list were not provided.

"Americans are fed up with special interest earmarks that have been at the center of recent scandals," says Sen. Jim DeMint (R) of South Carolina, who blocked moves to a conference on lobby and ethics reform until he had assurances from Senate majority leader Harry Reid that strong earmark provisions would remain in the final bill. "It is ironic that Senator Reid has seen fit to rewrite a bill in secret that is supposed to provide transparency and sunlight. I'm especially disappointed in Speaker Pelosi, who started this debate with strong rhetoric for earmark disclosure. She completely yielded to Reid and pressure from lobbyists," he said in a statement.

Some public interest groups are backing Senator DeMint in what they see as a lively floor fight in the Senate, expected on Thursday. "The taxpayers' worst fears have been realized. Prototypical of Washington backroom deals, House and Senate Democrats have conjured up a deal that benefits only the powerful appropriators and the special interests that game the system at the expense of average Americans," said Tom Schatz, president of the Council of Citizens Against Government Waste.

But many other open-government groups praise the legislation for moving reform further than it has gone in any previous Congress.

"If you compare where we were in 2006, it's a giant step forward. It could have been two giant steps forward," says Bill Allison, senior fellow for the Sunlight Foundation, a public interest group that promotes transparency in government.

A key provision that was dropped in the final version of this bill would have made lists of congressional earmarks available on a searchable database. The new version makes that requirement only "if technically feasible."

"This is something Amazon.com does every day with its eyes closed," says Mr. Allison. "We're still going to be in a situation where public interest groups are going to have to get earmarks in a form that's usable. Congress should have done this itself and didn't."