Washington — A hulking, 635-page anti-crime bill was one of the biggest surprises of the recent congressional season. Left for dead in an obscure subcommittee, the bill leaped to its feet shortly before the 98th Congress was scheduled to end. It trampled all opposition, won quick passage, and on Oct. 12 was signed into law by President Reagan.
''I'm still pinching myself,'' says Patrick McGuigan, a judicial scholar at the Free Congress Foundation and a supporter of the legislation.
The bill makes historic changes in federal law, particularly in the areas of bail and sentencing. But since 99 percent of violent crimes prosecuted in the United States fall under state law, the bill's tough new provisions won't have a large effect on street safety.
Specifically, passage of the anti-crime package means federal judges can now refuse to set bail for defendants they deem ''dangerous'' to the community. These accused will be held in jail pending trial.
Thirty-two states already have similar laws, although most of these are narrower than their federal counterpart. Both the American Civil Liberties Union and the American Bar Association are troubled by this abolition of bail, which they feel includes some presumption of guilt.
''It's so difficult to predict 'dangerous,' '' notes William Greenhalgh, a criminal law professor at Georgetown University.
The anti-crime act will also completely renovate federal sentencing procedures. Under the terms of the bill, sentencing guidelines are to be developed by a presidential commission, in an attempt to ensure that criminals who have committed similar crimes receive similar punishments. Thus federal judges will have much less flexibility when determining how long - or whether - convicts should be locked up.
''There will be less disparity in sentencing, perhaps at the cost of other values,'' grumbles a Republican congressional aide. Critics worry that these guidelines will result in more people going to jail, for longer periods of time. When combined with another section of the crime bill, which eliminates parole for federal prisoners, the sentencing provision could well result in further overcrowding of prisons, the congressional aide says.
Other parts of the new bill increase the penalties for serious drug offenses and for repeat ''career'' criminals; reestablish a program of grants for state anti-crime efforts; and broaden US laws on computer crime and credit-card fraud. The legislation also redefines the insanity defense, in an attempt to restrict its use.
Politics played a large role in the bill's passage this year. A big omnibus crime bill passed the Senate in February. President Reagan then continually criticized the Democratic-controlled House for what he considered obstructionism on the issue; this pressure, combined with clever parliamentary moves by GOP representatives, finally caused the House to make major motion on crime.
''Crime was beginning to become an issue for a lot of House races,'' says Mr. McGuigan of the conservative Free Congress Foundation.
Front-line law-enforcement officials supported the bill. Gerald Arenberg, director of the National Association of Chiefs of Police, attended a convention of his members last week. ''They definitely were in favor of these changes,'' he says, ''the career criminal ones especially.''
But Mr. Arenberg points out that the vast majority of defendants are charged by state governments, not the US itself. In Maryland, for instance, there are about 15,300 state prosecutions for robbery each year. Maryland's federal court sees about 40 robbery cases annually.