Money, as the late House Speaker Tip O’Neill once said, is the mother’s milk of politics. And sometimes that milk can curdle, as shown by yesterday’s guilty plea by Jack Abramoff, whose huge lobbying network had been distributing money and favors to members of Congress.

Many lawmakers now are agonizing over whether a seat in Abramoff’s sky box at a Washington Redskins game, a dinner at Signatures, his former posh restaurant, or maybe an all-expenses golfing trip to Scotland will come up when Mr. Abramoff testifies at a government trial in a widening corruption scandal.

Some of them are already returning donations received from Mr. Abramoff or his clients, according to the Associated Press. Among them, the AP said, are Sen. Sam Brownback, a Kansas Republican said to have been weighing a presidential bid, and Sen. Conrad Burns, R-Mont., who has turned back $15,000.

Now, smaller gifts and favors are perfectly legal. To stay within a $50 limit, lobbyists sometimes give a lawmaker or a staffer a ball game seat priced at $40.

But Mr. Abramoff’s gifts, funneled through clients like Indian tribes, go far beyond any reasonable limit. Justice Department investigators are said to have 20 or more lawmakers and staff members in their sights as possible targets for prosecution.

Among those under scrutiny are former House majority leader Tom DeLay, R-Texas; Rep. Robert W. Ney, a Republican from Ohio, Rep. John T. Doolittle, R-Calif., and other members of Congress involved with Indian affairs, one of Mr. Abramoff’s major areas of interest. He is said to have sent an Indian tribe a list of members of Congress with a request that it distribute $90,000 among them. He has used a similar method to provide contributions by way of the another client, the Marianas Islands in the Pacific.

Still other possible targets of the investigations are several congressional wives to whom he has provided presents or jobs. The probe may also extend to Mr. Abramoff’s old partner, Grover Norquist, an anti-tax activist who has organized Washington lobbyists in the K Street Project, which is trying to assure that lobbying firms hire only conservatives.

Mr. Abramoff’s plea likely will inspire others under suspicion to try to cut deals before it is too late. But the scope of the investigation, no matter what else happens, will disrupt a Congress that last month demonstrated a lack of ability to govern. Things will get worse this winter as politicians or their aides or spouses are targeted. Congress will then have the opportunity to try once again to draw a workable line between legitimate political contributions and bribery.