Since the whiff of scandal began to emerge around Abramoff, members have been rushing to return his contributions or donate the money to charity. But not everyone who ever took Abramoff-related money or perks is guilty of wrongdoing.
"It's not enough to take a campaign contribution," says Mr. Brand. "What's criminal is accepting the contribution in return for an express agreement to perform an official act. Beyond campaign contributions, one can't accept bribes or gratuities of any kind in return for official acts." Members of the executive branch may also be implicated in the investigation, he says.
"The line between a bribe and a legal contribution is very thin, but it is that line that keeps you out of jail," says Larry Noble, executive director of the Center for Responsive Politics. "The critical element is whether there was an understanding or agreement to take specific action in return for the money."
Abramoff joins former associate Michael Scanlon, former press secretary to DeLay, as a witness for the prosecution. Mr. Scanlon reached a plea deal last year, which raised the stakes for Abramoff. The Department of Justice says the two men defrauded Indian tribes they represented out of tens of millions of dollars.
In exchange for the guilty plea and cooperation, Abramoff would probably get a reduced prison sentence. In the Washington case, he faces a maximum of 10 years; in the Florida case, in which he is pleading guilty to fraud and conspiracy in the purchase of a casino cruise line, he could get as many as seven years.
"Up until now, I've said it will involve just a few members," says Mr. Noble. "But if they've reached a plea agreement with Abramoff, it means he's turned over people higher than him, and they must have some pretty strong evidence.