Updated at 4:15 p.m. ET.
Accepting responsibility for the charges of ethical misconduct against him, Rep. Eric Massa (D-N.Y.) announced today he is resigning his seat in Congress, effective Monday.
"I do so with a profound sense of failure and a deep apology to all those whom, for the past year, I tried to represent as our Nation struggles with problems far greater than anyone can possibly imagine," Massa said in a statement on his Web site.
The freshman representative already announced this week he would not seek another term, citing a battle with cancer. While allegations had surfaced that Massa sexually harassed a male member of his staff, the congressman initially said the charges were unsubstantiated.
However, Massa said in his statement today that after he decided not to run again, he was told for the first time that a member of his staff believed he had made "statements that made him feel 'uncomfortable.'" A report on the incident has been filed with the Congressional ethics committee.
"I own this reality," Massa said. "There is no doubt in my mind that I did in fact, use language in the privacy of my own home and in my inner office that, after 24 years in the Navy, might make a Chief Petty Officer feel uncomfortable."
While accepting culpability, Massa said that, "with the destruction of our elected leaders having become a blood sport," an ethics investigation would tear his family and staff apart.
Massa's resignation may make it slightly easier for Democrats to get enough votes to pass a health care bill -- he was one of 39 House Democrats to vote against health care. He said the bill did not do enough to make the insurance industry competitive, among other things.
Republicans had been optimistic about overtaking Massa's seat in New York's right-leaning 29th congressional district.