House and Senate leaders have agreed to a new compromise surveillance bill that would effectively shield from potentially costly civil lawsuits telecommunications companies that helped the government wiretap citizens' phone and computer lines after the September 11 terrorist attacks without court permission.

The House will debate the bill on Friday, potentially ending a monthslong standoff about the rules for government wiretapping inside the United States.

House Majority Leader Steny Hoyer of Maryland said the new bill "balances the needs of our intelligence community with Americans' civil liberties, and provides critical new oversight and accountability requirements."

The issue of legal protection for telecommunications companies that participated in "warrantless wiretapping" has been the single largest sticking point. The Senate passed a bill that immunized them from lawsuits. The House bill was silent on the matter. The White House threatened to veto any bill that did not shield the companies, which tapped lines at the behest of the president and attorney general — but without permission from a special court established for this very purpose — the Foreign Intelligence Surveillance Court.

"Warrantless wiretapping" went on for almost six years until it was revealed by the New York Times. Some 40 lawsuits have been filed against the companies by people and groups who think they were illegally eavesdropped on by the government.

The compromise bill would have a federal district court review certifications from the attorney general saying the telecommunications companies received presidential orders telling them wiretaps were needed to detect or prevent a terrorist attack. If the paperwork is in order, the judge would dismiss the lawsuit.