(See Corrections and Amplifications item below.)

The best news about yesterday's White House-Democrat deal on overseas eavesdropping is that the ACLU and the anti-antiterror Internet mob are apoplectic. This can only be good for U.S. national security. Too bad the compromise also comes at the cost of a further erosion of Presidential war powers.

The deal would extend the 1978 Foreign Intelligence Surveillance Act to cover eavesdropping on terrorist communications overseas. A six-month extension – the Protect America Act – expired earlier this year and surveillance authorization on al Qaeda targets will start to expire in August. The new deal – assuming it isn't defeated by liberals on the House floor – would last for six years. It is thus a gift to the next President, who won't have to spend capital battling those who think that letting our spooks read al Qaeda's email inevitably means that Dick Cheney is bugging your bedroom.

On the bright side, the deal gives crucial immunity to the telecom companies that in good faith assisted this surveillance after 9/11. A reality of this Internet era is that the feds need these private companies to monitor terrorists; our spies can't merely bug the phones of Russian spies like they could during the Cold War. The left understands this and has hit the companies with some 40 lawsuits in an attempt to shut down the surveillance by the backdoor, without a political debate that voters might understand.

The telecom (and other) companies have thus made it clear that they can't afford to cooperate any longer without immunity. And so the deal will let the companies escape the lawsuits, for past and future cooperation, if they present to a federal judge a certification from the Attorney General that they are helping at federal request. The eavesdropping orders that expire in August can thus be renewed, so our security services won't have to "go dark" over the global antiterror battlefield.