Imagine a day in the future when everyone, from the moment they step outside their home, has to live with the knowledge that their every movement is being recorded by powerful cameras circling in the skies above. Not just where they work, shop, eat and drink, and whose homes they visit, but details about their political, religious, sexual, and medical lives — all captured and stored in databases without a warrant and available to law enforcement upon request.   That day is here.   The city of Baltimore is about to deploy a new program that, if allowed to move forward, would do just that. It would be the most significant new surveillance system to be deployed in the U.S. in decades, and it would fundamentally change what it feels like to venture out in public in this country. It also violates our constitutional rights to freedom of association and privacy, and — on behalf of a group of Baltimore community activists — we are suing to stop it today.   The technology is called wide-area aerial surveillance. It involves stationing an aircraft equipped with ultra-high-resolution cameras over a city to continuously track all visible pedestrians and vehicles within that city. Currently, the technology can cover a 32-square mile area, though better cameras are just an upgrade away. It was originally developed by the military for monitoring overseas battlefields in Iraq and Afghanistan in a program called “Gorgon Stare.” Now, a company called “Persistent Surveillance Systems,” founded by a colonel who worked on that program, wants to turn this mega-powerful “eye in the sky” inward onto American cities.   Although this company has been pitching American cities for years, no police department until now has been willing to embrace this truly dystopian technology. The term “Big Brother” is bandied about a lot these days, but rarely has a technology lived up to the term so well.   It’s no coincidence, of course, that this program is being unveiled in Baltimore, a city that’s more than 60 percent African American. Black and Brown communities in the U.S. are always first in line to come under surveillance by new technologies. Baltimore in particular has a terrible history of racism and a lack of accountability for abuses by police that makes it an especially problematic place to deploy this technology. In fact, the city is currently under a federal consent decree for routinely violating people’s constitutional rights.   Also quick to come under surveillance are those who seek to exercise their rights to demand change: political activists, protesters, and dissidents of all kinds. This includes our plaintiffs: Leaders of a Beautiful Struggle, a grassroots think-tank that advances the public policy interests of Black people in Baltimore, Erricka Bridgeford, co-founder of the Baltimore Ceasefire 365 project to end gun violence in the city, and Kevin James, a community organizer and hip-hop musician. Unfortunately, this country has a long history — continuing to the present day — of law enforcement using surveillance technology against people not because they are suspected of committing a crime, but because of their beliefs. In Baltimore, that has meant the targeting of Black Lives Matter protesters, who have been subjected to sweeping surveillance, including aerial surveillance.   If this program moves forward in Baltimore, we can expect it to quickly spread to other cities with large Black and Brown populations and histories of racial bias. But nobody in America should think that they’ll be able to evade this technology. If it moves forward in Baltimore, we can expect police departments around the country to start adopting it. Eventually, when drones are able to fly freely over our cities, making this kind of constant surveillance cheap and automatic, it wouldn’t be surprising if much of the country ends up covered.   Persistent Surveillance Systems is a tiny company, but if it succeeds in winning acceptance for its trial pilot program in Baltimore, there are much bigger companies waiting in the wings — companies that already advertise wide-area surveillance devices and would no doubt love for a domestic market to open up. These are companies that could put much more powerful technology overhead, including automated AI analysis, multi-spectral imaging, and night vision capabilities, not to mention much higher camera resolutions.   We are filing a lawsuit in the hopes of stopping this train. Based on ample precedent — including a landmark 2018 case that the ACLU won in the Supreme Court, Carpenter v. United States — we argue that tracking individuals in the way that this technology does is something the government cannot do without a warrant. There is no doubt, we argue, that people’s long-term physical movements, even in public places, enjoy constitutional protection.   The government certainly can’t track everyone in a city, because even with a warrant, that would violate the Constitution’s ban on “general warrants” — the kind of broad, non-individualized authorization to carry out searches that angered the Founders so much. If the Baltimore police want to track a citizen over wide areas and extended periods of time, they have to seek a warrant specific to that person. They don’t get to fill a data warehouse with records of everyone’s movements, which they can then pluck at will without asking a judge. In this respect, Baltimore’s plan echoes the National Security’s Agency’s secret seven-year collection of Americans’ telephone records — which was found to be unlawful in another ACLU lawsuit, ACLU v. Clapper.   Finally, we argue that this system violates not just the Fourth Amendment’s prohibition against “unreasonable searches,” but also the First Amendment’s protection of the right of assembly. As the Supreme Court has found, overbroad searches will have an “inevitable chilling effect” on constitutionally protected activity like protests and marches.   The Supreme Court has repeatedly made clear that, when faced with new technologies, it views the courts’ role as protecting the “degree of privacy against government that existed when the Fourth Amendment was adopted.” If the Founders could see what today’s police would like to do, they would be horrified — as should be every American today.