President Barack Obama defended classified programs to collect data on U.S. residents' telephone calls and foreign nationals' Internet activity as "modest encroachments" on privacy legally authorized by Congress and essential to thwarting terrorist attacks.

"In the abstract, you can complain about Big Brother, and how this is a potential program run amok," Obama told an audience in San Jose, California. "But when you actually look at the details, then I think we've struck the right balance."

The Obama administration confirmed the existence of the programs last night, a day after reports emerged of a secret court order compelling Verizon Communications Inc. (VZ) to provide the National Security Agency with data on all its customers' telephone use. While the revelations stirred outrage among privacy-rights advocates, U.S. lawmakers from both parties acknowledged earlier yesterday that they were aware of the Verizon order and backed the collection of telephone records as necessary to combating terrorism.

The revelation reignited a debate over the proper balance between civil liberties and security that has flared repeatedly since the Sept. 11, 2001, terrorist attacks. Yet the public backing the Obama administration received from lawmakers in the aftermath of the disclosures makes it unlikely Congress will act to limit the surveillance.

David Fuller's view President Obama's response sounds reasonable but data surveillance is a slippery slope. I think concerned Americans should ask if the IRS tax authorities have similar access to private information. In other words, is the IRS reading your private emails?