A frequent line of criticism of the “war on terrorism” framework that the United States has operated under for the past 17 years is that it’s not clear what would need to happen for this “war” to end. But now it appears it’s not clear when the “forever war” began, either.

As Carol Rosenberg of the Miami Herald reports, a military judge at Guantanamo Bay ruled this week that the United States was already engaged in armed conflict with al-Qaida at the time of the 9/11 attacks. Attorneys for Mustafa al-Hawsawi, a Saudi detainee at Guantanamo who is on trial alonside alleged 9/11 mastermind Khalid Sheikh Mohammed and several other defendants, had filed a motion to dismiss charges against their client. They argued that Hawsawi’s alleged offenses—helping some of the hijackers with funding and travel to the United States—took place before the U.S. was formally at war with al-Qaida. Therefore, they reasoned, he should not be charged by the military commission.

In his ruling on the motion, which was obtained and published by Just Security, the judge, Army Col. James L. Pohl, wrote that it is “unnecessary to decide a date certain for the commencement of hostilities” and that for the purposes of this ruling, armed conflict between the United States and al-Qaida existed “as of September 11, 2001, and for an indeterminate period before that date.”

This makes some sense. Osama Bin Laden issued his fatwa titled “Declaration of War against the Americans Occupying the Land of the Two Holy Places” in 1996, which Rosenberg notes is what prosecutors in this case consider the war’s starting point. Al-Qaida carried out attacks against the U.S. embassy in Africa in 1998 and the USS Cole in Yemen in 2000. The U.S. conducted missile strikes against al-Qaida targets in Sudan and Afghanistan in 1998.

But still, it’s a strange assertion. As attorney Steve Vladeck asks, “[H]ow many people (even inside the U.S. government) would seriously have thought, on September 10, 2001, that the United States was engaged in an ongoing armed conflict with al Qaeda?” What’s more, “Blind Sheikh” Omar Abdel Rahman and his co-conspirators in the 1993 World Trade Center bombing were convicted in civilian courts. (Bin Laden, then a little-known figure in the U.S., was identified but not indicted by the government as a potential co-conspirator in that attack.) Had the 9/11 attacks not occurred, and had Congress not passed an authorization for the use of military force against its perpetrators several days later, it stands to reason that captured al-Qaida members would have continued to be tried as civilians, fatwa or no.

That military authorization is, controversially, still in effect today and has been used as the legal basis for the detentions and prosecutions at Guantanamo as well as military actions against a number of groups around the world, some of which, such as ISIS, did not exist in 2001.

The concept of acts or declarations of war have become more complex and ambiguous in an era when more armed conflicts are typically fought not between states but between states and nonstate actors. (Though, as this week’s renewed hopes of a formal end to the Korean War remind us, countries can be in states of ambiguous semi-war with each other as well.) The legal framework of the war on terror has given the government an extraordinary amount of leeway to decide where and against whom the United States is engaged in armed conflict. It can apparently apply that framework retroactively as well.

While it may make some limited legal sense in this particular case, the ruling is a further reminder of just how muddy our distinctions between wartime and peacetime are becoming.