The congressman who has admitted he has mental health problems and has also fessed up to what he calls a "consensual" sexual encounter with a barely legal teenager, begged Nancy Pelosi over the weekend to keep his job.

Politico is reporting that he has agreed not to run for re-election in 2012, but that he refuses to resign:

"He isn't going to be running for reelection," a Wu adviser, speaking on the condition of anonymity, told POLITICO late Sunday night. "But he hasn't done anything that rises to the level of requiring him to resign."

With a defiant Wu staying put, House Minority Leader Nancy Pelosi (D-Calif.) called on the Ethics Committee to investigate the explosive allegations against him.

"I call on the Ethics Committee to initiate an investigation into the allegations against Congressman Wu," Pelosi said in a statement released after Wu's decision to stay put. "With deep disappointment and sadness about this situation, I hope that the Ethics Committee will take up this matter."

Pelosi said she would send a letter to the Ethics Committee on Monday "asking them to formally initiate a review of this matter."

The "matter" regards a "sexual enounter" that Wu had with the teenage daughter of a friend:

The woman left a "distraught" voice-mail at Wu's congressional office in Portland, a message heard by some of Wu's staffers. The woman "accused Wu of aggressive and unwanted sexual behavior," The Oregonian reported. A Democratic insider familiar with the call said the claims against Wu "were disgusting and appalling."

Wu has not commented on the incident beyond issuing a one-sentence statement Friday: "This is very serious, and I have absolutely no desire to bring unwanted publicity, attention or stress to a young woman and her family."

Given the congressman's well known mental health issues, as well as this latest outrage, he should step down. But he won't. The Democrats will not put enough pressure on him to leave office, desiring the "D" sitting in the seat rather than doing what's right for the dignity of the House and the congressman's constituents.