The House on Thursday is expected to vote on legislation reforming the National Security Agency's phone metadata spying program, a package that some civil rights groups quit backing following 11th-hour changes supported by the Obama administration.

"It's too watered down for us to be able to support it," Kevin Bankston, policy director of the Open Technology Institute, said in a telephone interview.

The House Rules Committee dramatically altered the USA Freedom Act package Tuesday, despite two other House panels forwarding more privacy-laden legislation to the House weeks ago.

The American Civil Liberties Union scoffed at the outcome. “The USA Freedom Act leaves much to be desired, and it is a limited first step in the direction of reforming mass surveillance practices. The Senate will have to make extensive improvements to satisfy the concerns of the American people over mass surveillance, and we will fight to make that happen," Laura Murphy, director of the ACLU's legislative office, said in a statement.

Here's what the revised legislation does:

Instead of the NSA collecting and housing the metadata from every phone call made to and from the United States, that data will remain in the hands of the telecoms. There were no laws barring the NSA from searching the data carte blanche, although the agency promised it would only do so if it had a "reasonable articulable suspicion" against a terrorism target.

The USA Freedom Act, however, demands that the NSA get approval for a search from the Foreign Intelligence Surveillance Court before demanding that the telecoms hand over metadata.

Under the act, a database search inquiry is allowed if it is “a discrete term, such as a term specifically identifying a person, entity, account, address, or device.” Until Tuesday, an allowable search under the USA Freedom Act was defined as “a term used to uniquely describe a person, entity, or account.”

"It's now dangerously broad and vague," Bankston said, suggesting the new terminology allows for "phone records of all calls in an area code."

The phone metadata includes the numbers of both callers, the duration and time of a call, international mobile subscriber identity numbers of mobile callers, and calling card numbers.

Even before the legislation was weakened Tuesday, civil rights groups were skeptical of the USA Freedom Act but backed it because they knew it was among the best packages they could get from lawmakers. Among other reasons, the plan had won their support because it sets into law that the NSA may demand that metadata from a target be expanded two degrees, or two hops. That greatly increases the number of people the NSA can eyeball beyond the original target.

However, before NSA whistleblower Edward Snowden leaked the existence of the program last year, the government was jumping three degrees, or three hops away from the original target.

The revised package faces an uncertain House floor vote Thursday.

In the meantime, a Senate panel months ago had approved a package similar to the USA Freedom Act before revisions were made to it Tuesday. All of which means that the state of NSA reform is up in the air.

Bankston has provided Ars his briefing paper (PDF) detailing the extent to which the USA Freedom Act has been watered down.