We begin with a high stakes face-off over security and spying in america. It's about the nsa and that controversial campaign to collect information on the phone calls of ordinary americans. The white... See More
We begin with a high stakes face-off over security and spying in america. It's about the nsa and that controversial campaign to collect information on the phone calls of ordinary americans. The white house called it a key weapon in the fight against terror. Today a federal judge delivered a body blow, calling the program simply unconstitutional. Abc's chief white house correspondent jonathan karl starts us off. Reporter: This is a direct challenge to a program that the is the says has saved lives. The federal judge declared flatly that he believes the program is unconstitutional. It may be the ultimate victory for nsa hacker edward snowden, classified documents he leaked revealed just how much information the nsa collects on americans and directly led to today's ruling. At issue, the nsa's massive data base on virtually every phone call made in the united states. Today the federal judge, a george w. Bush pointy said the program almost certainly does violate a reasonable expectation of privacy and is indeed an unreasonable search under the fourth amendment. He called the government program that stores the phone data of virtually every american almost orwellian. But the president has long said the program and another that tracks information on e-mail is a critical tool in keeping the country safe. We've saved lives. We know of at least 50 threats that have been averted because of this information, not just in the united states but in some cases threats here in germany. So lives have been saved. Reporter: But today the judge said there is an utter lack of evidence that a terrorist attack has ever been prevented because searching the nsa data base was faster than other investigative tactics. The program is limited to collecting information on who called whom and from where and is not eavesdropping. When it comes to telephone calls, nobody is listening to your telephone calls. That's not what this program is about. Reporter: Despite the judge's strong language, the program will continue as the government pursues an almost certain appeal and diane, make no mistake. This is just the beginning of a battle that will go or almost certain to go all the way to the supreme court. Back to snowden because we are hearing a number on the number of documents he may have had in his possession. One million or more? Reporter: That's right. We know publicly they have said 200,000 documents at least snowden got ahold of. That's easily over one million pages. The scariest thing is tell tense doesn't know all of what he has. There is a prospect of seeing more from edward snowden. Thank you so much, john.
This transcript has been automatically generated and may not be 100% accurate.