House ethics committee leaders stood up for their Republican members Friday, insisting the lawmakers could act impartially in deciding whether Majority Leader Tom DeLay (search) misused his office.

Chairman Joel Hefley (search), R-Colo., and senior Democrat Alan Mollohan (search) of West Virginia defended the GOP committee members against conflict-of-interest questions raised by congressional watchdog groups and Democratic House candidates.

The private groups have insisted that an outside counsel conduct an investigation, since Republicans would be investigating the floor leader who controls the bills that come to a vote and has supported lawmakers with political contributions.

In recent days, with three DeLay political associates indicted in Texas in a campaign finance case, some Democratic candidates are stepping up attacks — insisting that Republicans return donations from DeLay's political action committee.

Robert Matsui, chairman of the Democratic Congressional Campaign Committee, called on Rep. Steven LaTourette, R-Ohio — an ethics committee member — to give back $10,000 in contributions from DeLay's PAC. LaTourette has told reporters he would not be influenced by the donations.

Hefley and Mollohan have placed allegations that DeLay misused his office before the full, 10-member Committee on Standards of Official Conduct, which is evenly divided by party.

The committee has not yet decided whether to dismiss the allegations or appoint an investigative subcommittee to probe some or all of the allegations by freshman Democratic Chris Bell, D-Texas.

Bell lost his primary after DeLay, also of Texas, engineered a redistricting plan that changed legislative boundaries.

DeLay is accused of soliciting political contributions for legislative favors, improperly contacting aviation authorities for political purposes and campaign finance violations.

DeLay has called the ethics allegations and the Texas indictment politically motivated. He has given the ethics committee an extensive response, but has not made it public.

DeLay's political action committee gave $81,077 in the last decade to 10 Republicans who are part of a pool who could be chosen to serve on an investigative subcommittee in the case. Four of the five committee Republicans were among those receiving contributions.

"It is important to state emphatically our belief in the integrity and ability of every member of this committee," Hefley and Mollohan said in a written statement.

"Both of us are confident in the ability of each of our fellow members, without exception, to execute their responsibilities faithfully and fairly, regardless of any political affiliations or personal relationships. If either of us believed that any committee member were unable to discharge his or her duties properly, we would seek to have that member removed from the committee."

Several congressional watchdog groups were not swayed.

Melanie Sloan, executive director of Citizens for Responsibility and Ethics, said, "It's so typical of the ethics committee. They'll excuse any behavior. This is just another attempt to whitewash unethical behavior."

Fred Wertheimer, president of Democracy 21, said, "There's an inherent conflict and tension when members of one party are asked to investigate a powerful leader of that party in the House."

The committee has named outside investigators in the past in high-profile investigations, including the probe of former House Speaker Newt Gingrich.

Bell accused DeLay of soliciting corporate contributions in return for help on legislation. He also contends DeLay improperly used his staff to ask U.S. aviation authorities to track down Texas Democratic legislators who had fled the state while trying to thwart DeLay's redistricting plan.

The third allegation accuses DeLay of using political action committees to distribute money from corporations in violation of Texas law.