WASHINGTON, Nov. 21 - Michael Scanlon, former aide to a powerful congressman and onetime partner of a wealthy lobbyist, pleaded guilty today to a federal conspiracy charge as part of a deal in which he agreed to cooperate with an investigation into possible wrongdoing by some lawmakers.

Michael Scanlon agreed to pay restitution totaling more than $19 million to the tribes and faces up to five years in prison.

Mr. Scanlon's comedown from a young and wealthy Washington power-player to disgraced felon, formalized before Judge Ellen Segal Huvelle of Federal District Court here, had been expected. But it still may have sent shivers down Capitol corridors.

Mr. Scanlon agreed to pay restitution totaling more than $19 million to the tribes and faces up to five years in prison. He was allowed to remain free on $5 million bond. After pleading guilty, the well-tanned Mr. Scanlon appeared incongruously cheerful. Asked by reporters why he was smiling, he replied, "I'm always smiling."

Mr. Scanlon, 35, was accused of conspiring to defraud Indian tribes out of millions of dollars as part of a lobbying and corruption scheme that involved wining and dining of some lawmakers, treating them to lavish trips and contributing to their campaigns.

Representative Bob Ney, an Ohio Republican, who heads the House Appropriations Committee, was alluded to in the indictment (although not by name) as a main beneficiary of largess, in return for helping Mr. Abramoff and Mr. Scanlon with their clients.

Lawyers involved in the case have confirmed that Mr. Ney is the "Representative #1" cited in the indictment. The congressman - who has not been charged - has asserted that he was duped by the two and is cooperating with prosecutors, a spokesman for Mr. Ney says.

Mr. Scanlon's lawyer, Plato Cacheris, was asked whether any other members of Congress had anything to fear. "I have no comment on that," he replied.

Until recently, Mr. Scanlon occupied a powerful - and lucrative - position at the intersection of political power and lobbying influence. For several years, he worked as a top aide to Representative Tom DeLay of Texas, the Republican majority leader. He left Mr. DeLay's office in 2000 to become an associate of Jack Abramoff, a Republican lobbyist.

Mr. Abramoff and Mr. Scanlon earned more than $80 million representing a few wealthy Indian tribes on gambling issues. Those transactions have been under investigation by the Senate Indian Affairs Committee as well as federal prosecutors.

In an e-mail message made public by the committee, Mr. Scanlon seemed to lust for wealth, and seemed to see the Indian tribes as easy targets. "I want all their money!!!" he wrote of one tribe in 2002. Referring to the money available from another tribe, he exclaimed, "Weeez gonna be rich!!!"

Mr. DeLay has been indicted in Texas on charges involving political fund-raising that are not related to the inquiry in which Mr. Scanlon pleaded guilty today. And Mr. Abramoff has been indicted in Florida on unrelated fraud-and-conspiracy charges involving an attempt to buy a fleet of casino boats.

Like Mr. Ney, Mr. DeLay has been named as a beneficiary of Mr. Abramoff's and Mr. Scanlon's generosity. He, too, has denied wrongdoing. Mr. Cacheris, when asked whether Mr. DeLay had reason to worry over Mr. Scanlon's cooperating with prosecutors, said, "You'll have to ask his lawyers."

Commentary:
Now we wait to see how many members of congress are brought down. Almost three dozen law makers are involved. I hope they can bring down at least 1/3 of them. The problem stems from a Supreme Court ruling that basically said "money is free speech.' The rest of us call it bribery.