WASHINGTON — Bowing to President Bush’s demands, the Senate approved and sent the White House a bill today to overhaul bitterly disputed rules on secret government eavesdropping and shield telecommunications companies from lawsuits complaining they helped America spy on Americans.

The relatively one-sided vote, 69-28, came only after a lengthy and heated debate that pitted privacy and civil liberties concerns against the desire to prevent terrorist attacks. It ended almost a year of wrangling over surveillance rules and the president’s warrantless wiretapping program that was initiated after the Sept. 11, 2001, terrorist attacks.

The House passed the same bill last month, and Mr. Bush said he would sign it soon.

Opponents assailed the eavesdropping program, asserting that it imperiled citizens’ rights of privacy from government intrusion. But Mr. Bush said the legislation protects those rights as well as Americans’ security.

“This bill will help our intelligence professionals learn who the terrorists are talking to, what they’re saying and what they’re planning,” he said in a brief White House appearance after the Senate vote.

The bill is very much a political compromise, brought about by a deadline: Wiretapping orders authorized last year will begin to expire in August. Without a new bill, the government would go back to old FISA rules, requiring multiple new orders and potential delays to continue those intercepts. That is something most of Congress did not want to see happen, particularly in an election year.

The long fight on Capitol Hill centered on one main question: whether to protect from civil lawsuits any telecommunications companies that helped the government eavesdrop on American phone and computer lines without the permission or knowledge of a secret court created by the Foreign Intelligence Surveillance Act.

The White House had threatened to veto the bill unless it immunized companies such as AT&T Inc. and Verizon Communications Inc. against wiretapping lawsuits.

Forty-six lawsuits now stand to be dismissed because of the new law, according to the American Civil Liberties Union. All are pending before a single U.S. District Court at California. But the fight has not ended. Civil rights groups are already preparing lawsuits challenging the bill’s constitutionality, and four suits, filed against government officials, will not be dismissed.

Numerous lawmakers had spoken out strongly against the no-warrants eavesdropping on Americans, but the Senate voted its approval after rejecting amendments that would have watered down, delayed or stripped away the immunity provision.

The lawsuits center on allegations that the White House circumvented American law by going around the FISA court, which was created 30 years ago to prevent the government from abusing its surveillance powers for political purposes, as was done in the Vietnam War and Watergate eras. The court is meant to approve all wiretaps placed inside America for intelligence-gathering purposes. The law has been interpreted to include international e-mail records stored on servers inside America.

“This president broke the law,” declared Senator Feingold.

The Bush administration brought the wiretapping back under the FISA court’s authority only after The New York Times revealed the existence of the secret program. A handful of members of Congress knew about the program from top secret briefings. Most members are still forbidden to know the details of the classified effort, and some objected that they were being asked to grant immunity to the telecoms without first knowing what they did.

Senator Specter compared the Senate vote to buying a “pig in a poke.”

But Senator Bond, one of the bill’s most vocal champions, said, “This is the balance we need to protect our civil liberties without handcuffing our terror-fighters.”

Just under a third of the Senate, including Senator Obama, supported an amendment that would have stripped immunity from the bill. They were defeated on a 66-32 vote. Senator McCain did not attend the vote.

Mr. Obama ended up voting for the final bill, as did Mr. Specter. Mr. Feingold voted no.

The bill tries to address concerns about the legality of warrantless wiretapping by requiring inspectors general inside the government to conduct a yearlong investigation into the program.

Beyond immunity, the new surveillance bill also sets new rules for government eavesdropping. Some of them would tighten the reins on current government surveillance activities, but others would loosen them compared with a law passed 30 years ago.

For example, it would require the government to get FISA court approval before it eavesdrops on an American overseas. Currently, the attorney general approves that electronic surveillance on his own.

The bill also would allow the government to obtain broad, yearlong intercept orders from the FISA court that target foreign groups and people, raising the prospect that communications with innocent Americans would be swept in. The court would approve how the government chooses the targets and how the intercepted American communications would be protected.

The original FISA law required the government to get wiretapping warrants for each individual targeted from inside America, on the rationale that most communications inside America would involve Americans whose civil liberties must be protected. But technology has changed. Purely foreign communications increasingly pass through American wires and sit on American computer servers, and the law has required court orders to be obtained to access those as well.

The bill would give the government a week to conduct a wiretap in an emergency before it must apply for a court order. The original law said three days.

The bill restates that the FISA law is the only means by which wiretapping for intelligence purposes can be conducted inside America. This is meant to prevent a repeat of warrantless wiretapping by future administrations.

The ACLU, which is party to some of the lawsuits that will now be dismissed, said the bill was “a blatant assault upon civil liberties and the right to privacy.”