WASHINGTON – In a slap at President Bush, lawmakers voted yesterday to block the Justice Department and the FBI from using the Patriot Act to peek at library records and bookstore sales slips.

The House voted 238-187 despite a veto threat from Mr. Bush to block the part of the anti-terrorism law that allows the government to investigate the reading habits of terror suspects.

The vote reversed a narrow loss last year by lawmakers concerned about the potential invasion of privacy of innocent library users. They narrowed the proposal this year to permit the government to continue to seek out records of Internet use at libraries.

The vote came as the House debated a $57.5 billion bill covering the departments of Commerce, Justice, and State. The Senate has yet to act on the measure, and GOP leaders often drop provisions offensive to Mr. Bush during final negotiations.

“This is a tremendous victory that restores important constitutional rights to the American people,” said Bernard Sanders, an Independent of Vermont, the sponsor of the measure. He said the vote would help “rein in an administration intent on chipping away at the very civil liberties that define us as a nation.”

Congress is preparing to extend the Patriot Act, which was passed quickly in the emotional aftermath of the September 11, 2001, terrorist attacks. Then, Congress included a sunset provision under which 15 of the law’s provisions are to expire at the end of this year.

Supporters of rolling back the library and bookstore provision said that the law gives the FBI too much leeway to go on fishing expeditions on people’s reading habits and that innocent people could get tagged as potential terrorists based on what they check out from a library.

“If the government suspects someone is looking up how to make atom bombs, go to a court and get a search warrant,” said Rep. Jerold Nadler, a Democrat of New York.

Supporters of the Patriot Act countered that the rules on reading records are a potentially useful tool in finding terrorists and argued that the House was voting to make libraries safe havens for them.

“If there are terrorists in libraries studying how to fly planes, how to put together biological weapons, how to put together chemical weapons, nuclear weapons … we have to have an avenue through the federal court system so that we can stop the attack before it occurs,” said Rep. Tom Feeney, a Republican of Florida.

Last year, a similar provision was derailed by a 210-210 tie after several Republicans were pressured to switch votes. In the meantime, a number of libraries have begun disposing of patrons’ records quickly so they won’t be available if sought under the law.

Attorney General Gonzales told Congress in April that the government has never used the provision to obtain library, bookstore, medical, or gun sale records.