Despite stern threats from President Bush, the House let a controversial wiretapping law expire today. This makes lawmakers vulnerable to charges that they are soft on terrorism, but more likely the situation may show that a more narrowly tailored law is sufficient.

The Senate earlier this week easily passed legislation giving the government more authority to eavesdrop on telephone calls, e-mails and text messages. Although the target of the surveillance is suspected terrorists, the law allows monitoring of some communications made or received by Americans.

Among the most troubling aspects of the Senate bill is a provision to grant immunity to telecommunications companies that cooperated with the government to allow monitoring of communications, even though these companies may have broken the law by allowing or helping to conduct surveillance without a warrant from the government. Only one company, Qwest Communications, refused to cooperate until the government got the required warrants. Former company CEO Joseph Nacchio, convicted last year of insider trading, has alleged that the government withdrew opportunities for contracts after Qwest failed to cooperate with the National Security Agency.

Because the Justice Department has prevented states and others from determining the exact role of the companies, it is impossible to know whether they broke the law. Granting immunity without this knowledge is premature, and worse, it tramples on states’ rights to protect the privacy of their citizens.

The immunity provision is supported by Sens. Olympia Snowe and Susan Collins. It is opposed by Reps. Tom Allen and Mike Michaud.

The House refusal to approve the Senate bill, which contains the telecom immunity provision, sets up a contentious process to reconcile the two bills with the White House strenuously pushing for quick approval of the Senate bill.

This may not be necessary. First, the Protect America Act, which expires today, allows existing surveillance to continue until August. New wiretapping could be approved through the Foreign Intelligence Surveillance Act. In 1978, FISA set up a special court to consider requests for such warrants. Obtaining FISA court approval does not appear to be too difficult. The court has rejected, in part, only one application since 2005.

Still, the White House says that process is too slow and is seeking permission to eavesdrop without warrants on international communications before knowing whether all participants are outside the United States.

The White House also says changes are necessary because of the growth of electronic communications around the world. In Pakistan, where U.S. agents collect intelligence on al-Qaida and the Taliban, the number of cell phone users there grew from fewer than 3 million in 2003 to nearly 50 million last year, according to USA Today.

Much of this communication is routed through U.S. carriers and equipment, triggering protection under domestic wiretapping laws such as the requirement for search warrants.

Changes in communications technology require changes in surveillance techniques and their oversight. However, broad permission to eavesdrop on communications that pass through United States-based equipment goes too far. So does blanket immunity for telecommunications companies before state regulators can even determine what the companies did and whether they broke the law.