More Democrats Urge Weiner to Resign; Watchdog Sees Double Standard

Republican Sen. David Vitter (La.), who admitted to ties to the so-called D.C. Madam and later apologized, "actually committed a crime of soliciting a prostitute," said Sloan. He remains in office.

"I think there will be a public backlash when people start to think about what is this guy really accused of doing, and is this the most serious thing a politician has done when most people are really concerned about politicians selling their office to special interests?" Sloan said of Weiner. "There's no kind of that allegation here."

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In the end, should Weiner decide to stay, it will be the voters who decide his fate.

A Marist/NY1 poll found 51 percent of New Yorkers say Weiner should say in office, and only 30 percent think that he should resign.

Before his ethics trial and conviction, Rangel faced a New York Times poll that found 70 percent saying he should leave Congress -- 46 percent said at the end of his term, 24 percent immediately.

Several months later, however, Rangel was re-elected for a 21st term -- with 81 percent of the vote.

Note: This story has been corrected from an earlier version which incorrectly stated as fact that the Senate Ethics Committee determined Sen. Tom Coburn had lied about his involvement in the Sen. John Ensign matter. The committee did not reach such a conclusion.