Imagine the government has searched your home without a warrant or probable cause, rifling through your files, your bedroom dresser, your diary. You sue, arguing that the public record shows it violated your fourth amendment rights. The government claims that it has a defense, but that its defense is secret. The court dismisses the case.

That’s precisely what the federal government has increasingly said it can do in cases related to national security – under the so-called “state secret privilege”. It can violate constitutional rights, and then defeat any effort at accountability by claiming that its defense is secret – without even showing its evidence to a court behind closed doors.

The latest installment in this troubling trend involves the National Security Agency’s monitoring of Americans’ international internet communications.

Under a post-9/11 surveillance program known as “Upstream”, the NSA is systematically searching Americans’ internet communications as they enter and leave the United States. The agency sifts through these streams of data looking for “identifiers” associated with its many thousands of foreign targets – identifiers like email addresses and phone numbers. The NSA does all of this without warrants, without any individual judicial approval, and without showing that any of the people it is surveilling – including countless Americans – have done anything wrong.

This surveillance raises serious constitutional concerns, but no court has ever considered a legal challenge to it because the government has claimed that allowing a suit against Upstream surveillance to go forward would implicate “state secrets”.

Late last month, we filed a petition asking the US supreme court to make clear that the executive branch cannot invoke state secrets to dismiss cases challenging unlawful government conduct. The petition, which we filed on behalf of the Wikimedia Foundation (the non-profit that operates Wikipedia), explains that Upstream surveillance violates the privacy rights of Wikipedia users and Wikimedia itself. But the issue we’re asking the supreme court to decide has far broader implications for efforts to hold the government accountable for the most serious abuses.

Historically, the state secrets privilege was not a basis for dismissing cases. When the privilege developed in the early English and American courts, it allowed the government to withhold specific pieces of sensitive evidence. As with other privileges – like the attorney–client or priest–penitent privileges – the sensitive information was excluded, and the case would go forward without it. Sometimes the plaintiff would prevail using other available evidence, and sometimes they would lose. But they would have the chance to make their case in court.

In recent years, however, the government has invoked the state secrets privilege not as a shield but as a sword, to seek dismissal of cases even where the plaintiff can make its case using public evidence – as Wikimedia is willing to do.

In 2007, for example, an appeals court dismissed a lawsuit filed by Khaled El-Masri claiming that, in a case of mistaken identity, he had been kidnapped and tortured by the CIA. The court acknowledged the public evidence of El-Masri’s mistreatment but held that state secrets were too central to the case to allow it to go forward.

And in 2010, a different appeals court dismissed a lawsuit filed by five individuals who claimed that one of Boeing’s subsidiary companies had flown the planes carrying them to the black sites where they were tortured by the CIA.

This use of the state secrets privilege – to dismiss cases – departs from the supreme court’s narrow framing of the privilege. The court decided its seminal state secrets case, United States v Reynolds, in 1953, after three civilians died in the crash of a military plane. Their families sued and requested the flight accident report. In response, the government asserted the state secrets privilege, arguing that the report described secret military equipment.

The court acquiesced, but it emphasized that the plaintiffs could try to prove their case using other evidence. While the supreme court has accepted dismissal in a small set of cases involving secret espionage contracts, it has never blessed this approach for other cases, let alone ones involving allegations of serious constitutional violations.

In Wikimedia’s current lawsuit, the government has taken the maximalist approach. It has asked the courts to dismiss the case on state secrets grounds even though the government itself has released dozens of official reports, court opinions and other documents about Upstream surveillance.

Notwithstanding this public record, the lower courts threw out the case – without ever deciding whether this sweeping surveillance is constitutional.

The petition we filed gives the supreme court an important opportunity to rein in these over-broad invocations of secrecy. The court should instruct lower courts not to dismiss cases when the government invokes the state secrets privilege, but rather to use the array of tools that courts have long used to adjudicate cases involving sensitive information – for example, relying on security-cleared counsel, as courts routinely do in criminal cases, or examining secret evidence behind closed doors to assess its impact on a case.

Unless the supreme court steps in, the state secrets privilege will continue to be a “get out of jail free” card for the government – enabling it to violate the constitution with impunity by invoking secrecy.

• Patrick Toomey is deputy director of the American Civil Liberties Union’s National Security Project

• Alex Abdo is founding litigation director for the Knight First Amendment Institute