Do you use the internet? Are you interested in politics? Do you value your privacy? If you answered yes, you should be alarmed by the shockingly broad search warrant sought by the Justice Department, and approved by a judge in Washington, D.C., last month, targeting DreamHost, an internet hosting company based in Los Angeles.

As DreamHost explained in a blog post on Monday, it hosts disruptj20.org, a website that helped organize anti-Trump protests on Inauguration Day, and posted pictures of those protests in the days after. There were large-scale protests across Washington on Jan. 20, most of which involved peaceful marches or sit-ins. But some people turned to violence, breaking store windows, setting fires, throwing rocks at police officers and, in one case, assaulting Richard Spencer, the white nationalist, during a television interview. More than 200 people have been charged with felony rioting.

As part of its continuing investigation, the Justice Department demandedthat DreamHost turn over “all records or other information” relating to the site, which received more than 1.3 million requests to view its pages in six days after the inauguration. Those records include personal information like I.P. addresses, which identify a specific computer; data about which of the site’s pages a user viewed, and when; and the type of operating software on that person’s computer. Federal prosecutors are also seeking all emails, photos and other content sent to and from the site.

“That information could be used to identify any individuals who used this site to exercise and express political speech protected under the Constitution’s First Amendment,” DreamHost wrote in its blog post.

It doesn’t matter whether the visitor is suspected of participating in a crime, or is even known to have attended the protests. If someone clicked anywhere on the site from anywhere in the world, the government wants to know.

Prosecutors aim to vacuum up millions of points of data about people’s political associations, sift through it all and only then decide what they want — a process that has been used in other criminal investigations. But given that the investigation into the riots has been active for months, it shouldn’t be hard for prosecutors to narrow their search. DreamHost also objects that the warrant fails to provide any protocol for how investigators would examine the sprawling data, or explain what would happen to personal information that is found to be of no use in the case.

By forcing the government to defend this data sweep, DreamHost is doing an important service not only to its users, but also to the public at large. Prosecutors know that most companies don’t have the resources to fight such warrants, so a common tactic is to overreach and then wait for pushback. If the site or service provider folds and turns over the requested data, any constitutional violation may not be revealed until years later, when a diligent defense lawyer is challenging a conviction in a single criminal case. That’s a bad recipe for protecting all Americans’ right to freely associate, and to be free of unreasonable government intrusion, in the digital age.

This is a dangerous way for any Justice Department to conduct an investigation, especially one involving political speech and association, activities that enjoy the First Amendment’s strongest protections. As the Supreme Court said in a 1958 case, the “inviolability of privacy in group association may in many circumstances be indispensable to preservation of freedom of association, particularly where a group espouses dissident beliefs.” Sweeps like this have the potential to be even more chilling to speech when conducted under a thin-skinned president like Donald Trump, who has already made his intolerance of protest clear.