Everyone's heard of the Patriot Act. Here's what it actually does.

[Commentary] The Patriot Act has become a symbol of the massive expansion of government surveillance after 9/11. So if you're concerned about excessive government surveillance, or if you've ever talked with someone who is, you've probably heard or used "the Patriot Act" as a shorthand for the problem. That's not exactly right.

The Patriot Act was a big, broad law, and a lot of it has nothing to do with surveillance. And the government's current surveillance powers are drawn from some parts of the Patriot Act, but also from other laws. The current fight in Congress over surveillance programs has led to a lot of confusion about whether "the Patriot Act has expired." It hasn't; most of the Patriot Act is permanent. But three of the many, many individual provisions within the law expired, or "sunsetted," at the end of May 2015. The most significant of these is Section 215, which the government used to justify the National Security Agency's controversial phone records program. But other controversial programs remain in effect. And ultimately, the expiration of three Patriot Act provisions will have only modest effects on the government's spying powers.