Disclosure of secrets has been in the air these last few months. We've witnessed a remarkable stream of revelations about the National Security Agency's vast and invasive surveillance apparatus , followed by government disclosures concerning hidden intelligence programs and the secret court opinions that authorized them.

As a result, we now know many more details about the NSA's previously hidden domestic spying activities, capacities, and goals — secrets that, until June, we didn't know (even though we should have). Today, however, the ACLU will appear before a federal appeals court to argue for the release of so-called "secrets" that have been known to the public for years.

If that sounds like something out of Alice in Wonderland, don't worry — it practically is. The case being argued today in New York concerns a Freedom of Information Act request filed by the ACLU seeking the government's legal and factual bases for the "targeted killing" of three American citizens. The dispute before the appeals court principally concerns the gap between what the CIA maintains is secret about its involvement in targeted killing — that is to say, everything beyond its "intelligence interest" in the program — and what has been officially and publicly acknowledged by government officials. The district court ruled for the government in January, but admitted that the seeming absurdity of this result had the flavor of Lewis Carroll's classic.

First, the facts: For years, the national media has documented the United States' use of drones for the targeted killing of terrorism suspects in places like Pakistan, Yemen, and Somalia. The program is operated by both the U.S. military's Joint Special Operations Command and the CIA.

In September 2011, media outlets around the world reported the targeted killing by the United States of an American citizen, Anwar Al-Aulaqi, in northern Yemen. Killed in the same strike was another American, Samir Khan. And two weeks later, a U.S. drone killed Mr. Al-Aulaqi's 16-year-old American son with six other people at an open-air restaurant, also in Yemen. Shortly afterwards, the ACLU filed its FOIA request. (Reporters for The New York Times filed a similar request; the Times will be in court today as well.)

In the face of criticism and questions from across the political spectrum both before and after these killings, the government embarked upon what a federal appeals-court judge last year called a "pattern of strategic and selective leaks at very high levels of the government" to defend and justify its actions. While some officials spoke under cover of anonymity, others (perhaps some of the same ones) spoke publicly. For example, when Leon Panetta was director of the CIA, he addressed questions about the agency's use of drones on several occasions; later, as secretary of defense, he joked in a public speech to troops that the Predator drones he commanded at the CIA "weren't bad" military-grade weapons. John Brennan, the White House's top counterterrorism advisor, told one newspaper of his personal effort to shift responsibility for targeted killing from the CIA to the military. (Mr. Brennan now runs the CIA.)

More recently, both chairpersons of the congressional intelligence committees spoke on television, on the radio, and in press releases about their oversight of the CIA's use of drones. Mike Rogers, the House intelligence committee chair, went so far as to describe monthly meetings at the agency during which his committee views videos of recent strikes. And Dianne Feinstein, chair of the Senate intelligence committee, openly compared the CIA's record of drone-caused civilian deaths with that of the military.

Next, the rabbit hole: In 2011, the CIA responded to the two FOIA requests by refusing to "confirm or deny" whether it even possessed records related to the killings of the U.S. citizens. And in spite of the continuous stream of disclosures about the CIA's involvement in the U.S. targeted-killing program, the agency has barely budged. While it now concedes that it holds these records, it claims it cannot describe them in any way — with the exception of two public speeches made by government officials — without revealing state secrets.

The secrets the CIA is now protecting are not secrets in any genuine sense. Yet, today, a government lawyer will stand up in court to argue that something the entire world knows to be true — that the CIA is carrying out targeted killings — is something that this country's federal courts must pretend is unknown.

But, as my colleague Jameel Jaffer, who will argue before the appeals court today, put it:

The argument that releasing the legal memos would compromise national security is simply not plausible. Nor is the government's claim that other records can't be described or even listed. For several years now, senior officials have publicly claimed that the targeted killing program is effective, lawful, and closely supervised. If they can make these claims to the public, there is no reason why they should not be required to respond to requests under the Freedom of Information Act.

There is little question that some government secrets are legitimate. But the legal and factual basis for the government's killings of its own citizens cannot be. And the CIA's aggressive, unrelenting use of official secrecy to obscure facts already in the public domain—indeed, facts placed there by high-ranking government officials — has pushed its secrecy claim far beyond its breaking point.

The CIA's position is not only bewildering; it is dangerous. It threatens to undermine the credibility of our national security officials, the integrity of the courts, and our democracy's twin commitments to truth and transparency. As the summer's NSA revelations have shown, policies based on secret powers granted by secret laws are illegitimate from the start. If the government claims the power to kill Americans on the say-so of executive officials, the debate over the legality and wisdom of this policy belongs in the open.