By a lopsided 69-28 vote, the Senate has passed the so-called FISA compromise bill, extending the power of the executive branch to authorize warrantless interception of international communications, and effectively granting retroactive amnesty to telecoms that participated in the extralegal surveillance program authorized by President George Bush after the attacks of 9/11. Efforts to amend the legislation to delay the controversial immunity grant pending completion of an investigation by the Inspector General's office, to condition amnesty on a finding that the underlying surveillance was constitutional, or to strip immunity altogether, were soundly defeated—as expected—under threat of presidential veto.

Democratic presidential candidate Barack Obama (D-IL) voted in favor of the amendments to the Foreign Intelligence Surveillance Act, to the dismay of many of his own supporters. Majority Leader Harry Reid (D-NV) and Sen. Hillary Clinton (D-NY) were among those who broke with their party's standard-bearer to vote against the bill.

Civil liberties groups, including the American Civil Liberties Union and the Electronic Frontier Foundation, almost immediately issued statements condemning the vote. Both organizations pledged to challenge the new legislation in court. The Fourth Amendment will provide the probable basis for any challenge to the provisions permitting the executive branch to authorize electronic surveillance of overseas targets, even when in communication with Americans, without obtaining a probable cause warrant. The Supreme Court has already ruled unanimously that a warrant is required for domestic surveillance, even when conducted in the name of national security, but has never provided decisive guidance as to what the Constitution requires in the case of foreign intelligence surveillance that implicates the privacy rights of US citizens.

The legal grounds for a challenge to the immunity provision, which directs a federal court to dismiss the lawsuits against any telecom that received a written directive from the government authorizing surveillance, are somewhat less clear. But one possible approach was outlined earlier this year in a column by law professor Anthony Sebok. According to Sebok, the abrogation without compensation of a vested tort claim could be seen as a violation of the Fifth Amendment's Takings Clause. Similar sentiments were expressed on the Senate floor yesterday by Sen. Sheldon Whitehouse (D-RI). "I am aware of no precedent for the Congress of the United States stepping into ongoing litigation, choosing a winner and a loser, allowing no alternative remedy," said Whitehouse. "And I believe the constitutional problem with doing that as a separation of powers matter is particularly acute where the cause of action that is being litigated in the judicial branch is a constitutional claim." Whitehouse predicted that the immunity provision would ultimately be found unconstitutional.

While the legislative battle is over for the moment, the consequences of Sen. Obama's support for the bill, deeply unpopular with much of his "netroots" base, remain to be seen. Obama had previously pledged to oppose any bill containing retroactive immunity, but later committed to support compromise legislation even if amendments to strip that provision failed. The "Get FISA Right" campaign, which now boasts the largest user-created group on Obama's own social-networking site by a wide margin, will continue to exert heavy pressure on the candidate in the months to come. The group is circulating an open letter urging Obama to pledge to revisit the FISA bill as president.