Obama, speaking on the issue for the first time, praised Rangel for serving his New York constituents over the years, but said he found the ethics charges "very troubling."
"He's somebody who's at the end of his career. I'm sure that what he wants is to be able to end his career with dignity. And my hope is that it happens," Obama said in an interview that aired Friday on "CBS Evening News with Katie Couric."
As House members headed home for the August recess, they wrestled with how to handle the ethics brouhaha three months before the midterm elections. Republicans already were eager to use Rangel's problems as a way to tar other Democrats on the issue of corruption.
A half-dozen Democrats either conditionally or outright called for Rangel's resignation Friday.
Rep. John Yarmuth, D-Ky., said the allegations against Rangel brought by the House ethics committee show a consistent disregard for House rules and that he should step down.
"It is our job as members of Congress to hold each other accountable to a higher standard regardless of party," said Rep. Ann Kirkpatrick, D-Ariz. "If the serious charges against (Rangel) are accurate, he needs to resign."
Rangel denies the charges announced Thursday by the ethics panel and says they contain factual errors.
He met Friday with perhaps his staunchest supporters, members of the New York state delegation.
"He indicated there was some sloppiness" in his official papers, Rep. Edolphus Towns, D-N.Y., told reporters, "but, you know, there's no criminality here."
The New York delegation and the Congressional Black Caucus, which was co-founded by Rangel, urged their colleagues not to rush to judgment. House leaders were mum on what Rangel should do.
Rangel faces 13 charges of misusing his office as well as tax and disclosure violations. If Rangel and the ethics committee do not settle the case, it goes to a public trial this fall, at the height of an election season.
Further complicating matters for Democrats, a House investigative panel decided Friday to charge Democratic Rep. Maxine Waters of California with ethics violations, raising the possibility of a second trial. The alleged violations by Rangel and Waters are not related.
People familiar with the Waters investigation, who were not authorized to be quoted about charges that had not been announced, told the AP the allegations could be made public next week.
Republicans already were on the attack.
The GOP's campaign arm, the National Republican Campaign Committee, released a list of Democrats who have not returned campaign contributions they received from Rangel during their careers and said those lawmakers would face questions about the matter from constituents during the August break.
Rep. Gene Green, the Texas Democrat who led the four-member bipartisan panel of investigators, told reporters that his committee recommended a relatively mild punishment for Rangel: reprimand, a statement of wrongdoing voted by the whole House that carries no other penalty.
But that's not what some lawmakers, including Democrats, view as adequate.
"If at the trial's conclusion Mr. Rangel is found guilty by his peers, then he should incur the full punishment allowed by the House, including removal from office," said Rep. Bobby Bright, D-Ala.