The bill’s supporters say it’s the most far-reaching reform to U.S. surveillance programs in nearly 40 years. On the House floor, Conyers said the bill would put an end to “dragnet surveillance” in the United States. “Today, we have a rare opportunity to restore a measure of restraint to surveillance programs that have simply gone too far,” he said. Many privacy advocates, however, think it doesn’t go far enough to protect civil liberties. They’ve criticized provisions that expand surveillance powers by allowing access to data from more modern forms of communication, like video chats. And they say the proposal doesn’t sufficiently limit the search terms the NSA can use in requesting data and that it contains too many loopholes that would allow the government to access data in an emergency without a warrant. “It completely fails to meaningfully curtail mass surveillance and actually codifies some of the worst modern spying practices into law,” said Evan Greer, campaign director of Fight for the Future, an Internet-freedom advocacy group.

Activists also find little comfort in the fact that the bill has drawn support from the intelligence community and tech firms. An earlier version of the proposal passed the House last year but fell two votes of overcoming a filibuster in the Senate. The current bill is worse, Greer said, because it weakens transparency requirements and makes it easier for the government to cite “state secrets” and withhold information from a new “special advocate”created to serve as a watchdog for the FISA court.

What’s interesting is that supporters in both parties readily admit that the government will likely try to stretch the bounds of the new law just as it has with the Patriot Act. The difference, they say, is that the public will know when they’re doing it. “The government may one day again attempt to expand its surveillance powers by clever legal argument, but it will no longer be allowed to do so in secret,” Conyers argued.

There’s also recognition among some privacy advocates that although the Tea Party has helped elect more libertarian-minded conservatives to Congress, the USA Freedom Act is likely the most significant reform possible under majorities still led by old-school Republican national-security hawks, and at a time when fears of a terrorist attack remain ever-present. The ACLU, for example, is taking no formal position on the bill even though it sent lawmakers a list of areas in which it didn’t go far enough. That dynamic was on display this week when GOP House leaders rejected a bid by a group of younger libertarian members to offer amendments that would have further restricted the NSA. "This is a very delicate issue,” Speaker John Boehner explained to reporters. “I know members would like to offer some amendments, but this is not a place for people to bring out the wrecking ball.”