Former Sen. Russ Feingold was blunt in his assessment of the Obama administration's just-revealed intelligence gathering program: "I believe it's illegal":

Former Sen. Russ Feingold (D-Wis.) was the only senator to vote against the Patriot Act in 2001. (Brendan Hoffman/Bloomberg via Getty Images)After the Guardian revealed that the National Security Agency seized millions of Verizon customers' phone records through a secret court order, Rep. Jim Sensenbrenner (R-Wis.), one of the authors of the legislation that opened the door to this practice, said he was stunned.

"I do not believe the released FISA order is consistent with the requirements of the Patriot Act," Sensenbrenner wrote in a letter to Attorney General Eric Holder. "How could the phone records of so many innocent Americans be relevant to an authorized investigation as required by the Act?"

But this sort of data collection -- along with what the NSA is doing through itsPRISM program -- is exactly what then-Sen. Russ Feingold (D-Wis.) warned about when he was the only senator to vote against the Patriot Act in 2001.

From his speech:

One provision that troubles me a great deal is a provision that permits the government under FISA to compel the production of records from any business regarding any person, if that information is sought in connection with an investigation of terrorism or espionage.

Now we're not talking here about travel records pertaining to a terrorist suspect, which we all can see can be highly relevant to an investigation of a terrorist plot. FISA already gives the FBI the power to get airline, train, hotel, car rental and other records of a suspect.

But under this bill, the government can compel the disclosure of the personal records of anyone -- perhaps someone who worked with, or lived next door to, or went to school with, or sat on an airplane with, or has been seen in the company of, or whose phone number was called by -- the target of the investigation.

And under this new provisions all business records can be compelled, including those containing sensitive personal information like medical records from hospitals or doctors, or educational records, or records of what books someone has taken out of the library. This is an enormous expansion of authority, under a law that provides only minimal judicial supervision.