Images of federal bureaucrats as bumbling dolts adept only at shuffling meaningless memos were clarified last week by estimates of as much as $25 billion of fraud within government agencies. Only bureaucrats of stunning competence can filch that much.

The General Accounting Office reported to the Senate subcommittee on federal spending practices that Washington's in-baskets are the scenes of crimes involving bribery, doctored payment claims, kickbacks and collusion. Aside from the General Services Administration, which is in the news daily as the national fraud center, other agencies include the departments of Labor, Agriculture, Transportation, and Housing and Urban Development, the Veterans Administration and the Small Business Administration. "Everywhere we look for fraud, it's going to be there," said Sen. Lawton Chiles (D-Fla.) of the subcommittee.

With the government infested with white-collar thieves who have been mugging Uncle Sam with a pen, the robbed taxpayers now have a focus for their anger about excessive federal waste. The surge of outrage created by Proposition 13 has been refreshing, except that it has meant mostly cutbacks for social programs for the poor, or in budgets for libraries and schools. But a cutback on federal fraud could mean a painless saving of up to $25 billion.

Can anything be done - or is the corruption so pervasive and routinized that after a few committee hearings, some isn't-it-just-awful reports, some firings and perhaps a few convictions, the stealing must necessarily roll on by its immense momentum?

Some precedents for reform exist. In 1965, when the Office of Economic Opportunity began, a major part of the operation was the inspector general's office. An investigative reporter came in to run the shop, and through his auditing, spunk and general wariness about human nature and the yen for easy money, the agency stayed clean.

As befits the mentality of bureaucratic Washington, the OEO experiment was such a success that few other agencies copied the idea. Currently, only one department - HEW - has statutory authority for its own inspector general.

The Department of Health, Education and Welfare has 1,000 auditors in 42 locations looking for - and finding - fraud, waste and abuse. In Congress, an inspector general bill that would establish similar operations within all federal agencies is pending. When it was originally proposed, many of the frauds in mind were those pulled off by the so-called poverty cheats, as symbolized by that mythical high-rolling welfare mother in Chicago that Ronald Reagan forever babbles about. But now the cheats may be more on the government's rolls than the welfare rolls.

That's one legislative possibility. Chiles mentions two more: a sunset bill that would require Congress to examine periodically every agency and to judge whether its functions ought to continue and, second, a bill to protect whistle blowers.

These bills have gone through hearings, have picked up support and are no doubt useful. But they are in the grand - and getting grander - tradition of thinking up new laws to prevent the breaking of old laws. The GSA corruption already involves the violation of at least 20 statutes. Why not enforce the laws we have?

The answer to that has to do with fervor and the mystery of how to generate it in a society that had so little passion for honesty that it took two years to unload Richard Nixon after his deceits began. Politicians find their popularity enhanced when they pounce on one kind of criminal but not another. It is known that white-collar thieves - embezzlers, tellers, accountants - steal from banks six times the amount taken by old-fashioned robbers in ski masks. But the latter - usually the poor or uneducated - are sent to prison, while the others are treated leniently, if treated at all.

It is likely to be that way with government fraud. What could make a difference is a redirection of fervor. Citizens in a fury about federal spending need to realize that it isn't issue discovered yesterday by the New Right. To cut the excess means, at the bottom line of morality, to cut the fraud. And that means backing those politicians who, first, are free of it themselves and, second, are willing to make honest government a major political passion.