The Senate on Thursday put off voting on controversial electronic surveillance legislation, in spite of what appeared to be overwhelming support for the bill.

Sen. Russ Feingold, D-Wis., and more than a dozen other senators who oppose telecom immunity threw up procedural delays that threatened to force the Senate into a midnight or weekend session. The prospect of further delays was enough to cause Senate Majority Leader Harry Reid, D-Nev., to postpone the vote until after the weeklong July 4 vacation.

The bill provides legal immunity to telecommunications companies that helped the government wiretap American phone and computer lines without court permission after the Sept. 11 terror attacks.

It also makes it easier for the government to tap the calls and e-mails of terrorists. Its detractors contend that it does not protect Americans' privacy rights while its champions argue that it strikes the right balance between civil liberties and security. The bill passed the House with a strong majority last week.

Feingold and other critics of the legislation say civil lawsuits are the only way the country will learn the extent of the Bush administration's nearly six years of warrantless wiretapping. The surveillance took place without the permission or knowledge of the secret court Congress created 30 years ago to handle such activities.

The bill amending the Foreign Intelligence Surveillance Act represents a compromise. In exchange for telecom immunity, the inspectors general of the Pentagon, Justice Department and intelligence agencies will investigate the wiretapping program.

The attorney general and national intelligence director on Thursday said President Bush would veto the bill if the immunity provisions were stripped from it.