WASHINGTON -- Outside political groups known as 527s would face new contribution limits under legislation narrowly approved by the House yesterday.

The measure, which passed 218-209, is the first piece of the House Republican leadership's proposal to change the ethics and lobbying rules for Congress in response to scandals involving former lobbyist Jack Abramoff, who plead guilty to corruption charges, and former Rep. Randy "Duke" Cunningham, R-Calif., who resigned after admitting that he accepted bribes from defense contractors.

But the House legislation is unlikely to be approved by the Senate this year as a stand-alone measure, largely because it is opposed by many Democrats. They say Republicans are targeting the groups because their fund raising has been more helpful to the Democratic Party than to the GOP.

These 527 groups -- the designation comes from their classification under the Internal Revenue Code -- took a prominent role in campaigns after Congress passed the 2002 campaign finance reform bill, which prevented political parties from collecting unlimited donations from individuals.

With no limits on how much they could raise, 527 groups spent more than $400 million trying to affect the 2004 presidential campaign outcome, with much of that coming from just more than two dozen wealthy donors. They already have raised hundreds of thousands of dollars to influence the 2006 Pennsylvania races.

Under the legislation, which was sponsored by Reps. Christopher Shays, R-Conn., and Marty Meehan, D-Mass, contributions by individuals donating to 527s that are attempting to influence state and local elections would be capped at $25,000 and contributions to 527s involved in federal campaigns would be limited to $5,000.

Democrats said the 527 measure did nothing to address the abuses exposed by the Abramoff and Cunningham cases. The House's second-ranking Democrat, Rep. Steny H. Hoyer of Maryland, said the bill represented retaliation against Democrats as well as Republicans' fear of losing power in the fall elections.

Republicans said it was hypocritical for Democrats to argue that the GOP was trying to curb constituents' free speech with limits on donations, since many of the same Democrats opposing the 527 bill had supported the 2002 campaign finance bill.

If the Senate were to approve the House proposal, it could scale back activities of 527 groups like the Lantern Project, which has recently run ads in Pennsylvania critical of Sen. Rick Santorum, R-Pa., who is seeking re-election.

But a major criticism of the bill is that it does not include similar restrictions on other tax-exempt groups that have been involved in elections, including 501 (c) (3), 501 (c) (4) or 501 (c) (6) groups, which have virtually no disclosure requirements under current law.

One 501 (c) (6) group, Americans for Job Security, is airing ads this week in Philadelphia markets criticizing the amount of time that Democratic Senate candidate Robert P. Casey Jr. has spent at work as state treasurer.

Only six Democrats voted for the 527 bill, and 18 Republicans opposed it. Among Western Pennsylvania lawmakers, the measure was supported by Republican Reps. Phil English of Erie, Tim Murphy of Upper St. Clair, Melissa Hart of Bradford Woods, John Peterson of Venango and Bill Shuster of Blair. It was opposed by Democratic Reps. Mike Doyle of Swissvale and John Murtha of Johnstown.