WASHINGTON The ethical woes facing Democrats are piling up, with barely a day passing in recent weeks without headlines filled with word of scandal or allegations of wrongdoing.

The troubles of Gov. David Paterson of New York, followed by those of two of the state's members of Congress, Reps. Charles Rangel and Eric Massa, have added to the ranks of episodes involving prominent Democrats such as Eliot Spitzer, Rod Blagojevich and John Edwards.

Taken together, the cases have opened the party to the same lines of criticism that Democrats, led by Rep. Nancy Pelosi, now the House speaker, and Rahm Emanuel, now White House chief of staff, used against Republicans in winning control of the House and Senate four years ago.

The mix of power and the temptations of corruption can be a compelling political narrative at any time. But with voters appearing to be in an angry mood and many already inclined to view all things Washington with mistrust, the risks for Democrats could be that much greater this year.

Democrats, who are already on the defensive over the economy, health care and federal spending and are facing a re-energized conservative movement, suddenly have a set of ethical issues to deflect as well.

"Speaker Pelosi famously promised the most open, honest and ethical Congress in history," Rep. John Boehner of Ohio, the Republican leader, said Thursday. "Yet, here we go again."

In 2006, when Democrats were battling for control of the House, the message of their campaign against the Republicans could be boiled down to a three-word slogan: Culture of corruption. Democratic leaders aggressively seized on each indictment of a Republican member of Congress or lobbyist, building an argument that the controlling party had become arrogant and was in urgent need of a housecleaning.

So is that moment - in reverse fashion - now approaching for Democrats?

Tim Kaine, a former Virginia governor and chairman of the Democratic National Committee, said Thursday that the recent spate of allegations against several political figures in his party was troubling.

But he said the cases - largely revolving around New York politicians - had hardly reached the nationwide pitch that buffeted Republicans four years ago. Then, Tom DeLay, the Republican House leader, was indicted in Texas, and the influence-peddling scandal tied to the lobbyist Jack Abramoff touched several Republican members of Congress.

"I would never say that folks should be blithe about their ethical responsibilities. But I think it's quite a bit different," Kaine said Thursday. "But a couple things that happened in the same week in one state is different than the kind of corruption that roped members of Congress in from all over the country."

Pelosi moved quickly this week to deal with escalating criticism surrounding Rangel, who was admonished by the House ethics committee for accepting corporate-sponsored trips to the Caribbean. He remains under investigation on more serious accusations.

Since last Friday, 29 House Democrats have given back or donated to charity more than $400,000 in contributions from Rangel's three political fundraising committees. But several others have not returned the money.

Pelosi dismissed the criticism Thursday that Democrats had not lived up to their promise to sweep away a culture of corruption on Capitol Hill. She also noted that she had established an outside group to receive complaints about members of Congress, which could be easily referred to the House ethics committee.

"My commitment to the American people is that the public trust will always be honored," Pelosi said at her weekly news conference.

President Barack Obama, who built his campaign around a pledge to change the way Washington works and to strengthen transparency and ethics, has generally not commented on the scandals or allegations involving the Democratic politicians. Months ago, several of his senior advisers worked behind the scenes to try to dissuade Paterson from running for election, a pitch that failed.

Last week, Paterson conceded that he would not be on the ticket in the fall, but he has declined to step down. The White House has said that it has no intention of wading into the Paterson situation again, but several advisers said they were following the developments with interest.

It is the case of another governor, perhaps, that has drawn even more attention from those inside the West Wing.

Blagojevich, who was impeached last year as the governor of Illinois, faces a criminal trial in June. The proceedings are expected to be unfolding at the very moment that Democrats are battling in several races, including a campaign for the Senate seat once held by Obama.