Amid controversy over its surveillance practices, the National Security Agency faces a lawsuit by a man who claims a constitutional right to make fun of the agency.

McCall v. National Security Agency, filed on Wednesday in the District of Maryland, asked the court to declare that Dan McCall’s parody products do not violate federal laws protecting the government’s right to control use of agency names and seals.

McCall cited cease-and-desist letters from NSA and the U.S. Department of Homeland Security ordering online retailer and imprinter Zazzle.com to stop selling his products that parody the agencies. McCall sells his mugs, clothing and bumper stickers through a Zazzle.com virtual storefront.

In 2011 and 2013, the agencies sent three e-mails to Zazzle.com warning that products bearing certain images violated laws against using governmental seals. The first email indicated that Zazzle.com’s service terms barred vendors from selling items that might infringe on any intellectual or proprietary rights.

The disputed designs included the NSA’s seal and the words, “Spying On You Since 1952.” Another bore an altered version of the seal with the words, “The NSA: The only part of government that actually listens.” A third bore an altered version of Homeland Security’s seal with the words, “Department of Homeland Stupidity.”

The agencies’ actions are “not consistent with the First Amendment,” said Ezra Gollogly, a partner at Baltimore’s Kramon & Graham, one of McCall’s pro bono lawyers. “The idea that citizens can’t criticize the government through humor is not acceptable.”

Public Citizen of Washington is assisting McCall—also on a pro bono basis, said attorney Paul Alan Levy. The case was worthwhile, he said, “particularly given that these two agencies are in the news and subject to perhaps justified criticism for other civil liberties abuses.”

It’s not clear whether the agencies’ top management was on board with the warnings, Levy said. Still, the case reminded him of corporations tarred as trademark bullies for aggressively enforcing trademark rights against much smaller operators. In some cases, a company thus criticized “can’t justify suing on other grounds, so they bring a trademark suit.”

Homeland Security did not respond to a request for comment. In an email, the NSA cited Public Law 86-36, which says that no one can “use the initials ‘NSA,’ the words ‘National Security Agency’ and the NSA Seal without first acquiring written permission from the Director of NSA.” The agency is headquartered in Fort Meade, Md.

Sheri Qualters can be contacted at squalters@alm.com.