In the past, wars ended.
They ended when two warring nations signed a treaty; one reached its objective in seizing control of a resource; one was wiped from the map or for any number of other reasons.
The armed conflict the United States finds itself tangled in today is so much hazier and more complicated, even war experts have difficulty envisioning how it'll end.
"It's not clear how you thoroughly subdue terrorist groups or how you know you've done it," law professor Laurie Blank said during a lecture Wednesday. "It's hard to identify that moment. We find ourselves with possibility of perhaps maintaining perpetual state of conflict."
Blank spoke during Westminster College's Hancock Symposium. She's Director of the Center for International and Comparative Law and Director of the International Humanitarian Law Clinic at Emory University School of Law, where she teaches the law of armed conflict and works directly with students to provide assistance to international tribunals, non-governmental organizations and militaries around the world on issues in humanitarian law and human rights.
Additionally, she was co-director of the End of War Project, a multi-year project exploring a range of legal, policy, moral and strategic challenges in ending complex counterterrorism and counterinsurgency conflicts.
As she explained, international law and agreements govern how nations and groups may behave during an armed conflict (the legal term used in place of "war," a word weighed down by political rhetoric).
"(And there's) a lot of work in international law for figuring out when armed conflict starts - dealing with crime or unrest or war?" she said.
But the legal definition for the end of armed conflict is a lot looser - it's over at the end of hostilities, when the last shot is fired. When one of the warring factions is a terrorist group, perhaps with no clear leader and with members who act independently, it's hard to tell whether the group is truly defeated or just biding its time.
That's part of why the United States finds itself in its current situation.
"Last Friday was the 19th anniversary of 9/11," Blank said. "Pretty much anyone under 30 has no memory of the US not being at war with some group somewhere in the world. That's actually a pretty extraordinary statement."
Less than a month after the terrorist attacks in 2001, the U.S. Congress passed a joint resolution authorizing the use of force "against those nations, organizations, or persons he determines planned, authorized, committed, or aided the terrorist attacks that occurred on September 11, 2001, or harbored such organizations or persons, in order to prevent any future acts of international terrorism against the United States by such nations, organizations or persons."
As Blank pointed out, that's a broad scope. Soon, troops were in Afghanistan pursuing the Taliban and al-Qaida.
"It's pretty broad and it has been stretched beyond recognition," Blank said. "We're fighting against groups that didn't exist at the time of 9/11."
Today, the United States is still engaged against al-Qaida, along with other groups including al-Shabaab and the Islamic State group. Our troops are stationed in dozens of countries and providing counterterrorism training in many more.
"The question is, can this just go on and on?" Blank asked. "Apart from the strategic objective is there an obligation simply to bring it to an end?"
Legally, the answer appears to be no. International law and bodies such as the United Nations don't actually require states make an attempt to end their wars, nor has the United States passed any laws to that effect. As Congress authorized the use of force in the first place, they might be able to rescind that authorization, but "Congress hasn't really shown its teeth in the constitutional use of force space in an effective way in a very long time," Blank said.
If anything, perpetual war creates a strategic advantage to the United States, she said. That's because international law has different requirements for behavior in war-time versus peace-time. When two states are at war, and one side identifies a member of the enemy forces, they can kill that person as a matter of first resort - there's no obligation to make an arrest and prosecute the person.
"You don't have to wait for them to shoot at you, you don't have to ask if they're actually hostile their very membership in that enemy force makes them hostile," Blank said.
Likewise, you can detain people you suspect to be enemy combatants until the end of the conflict, with no charges or prosecutorial process.
"It's not unreasonable to say that from the U.S. perspective, (it makes sense to) maintain a situation in which you have the legal framework of conflict, which provides greater flexibility in thinking about how go after these types of groups," Blank said. "If you determine it's over, then next time we encounter one of these groups posing a threat, we're not in place where we can use force as a first resort. Now we have a more limited set of authorities."
Between the strategic advantage and the difficulty in declaring victory over groups that could reemerge at any time, the United States has had back-to-back presidents promising to "bring the troops home" and failing to do so - the situation is simply more complicated than that, according to Blank.
"The administration doesn't actually want to say 'We've changed our mind, we want to leave more troops there,'" Blank said. "So now they've come up with reasons: 'Well, we're defending the oil, we're guarding this, we're guarding that.' That opens up new questions - can you really leave troops in another country to guard oil facilities? I don't really think so."
Blank pointed out while perpetual war might be a strategic tool, "it comes at a cost" - there's a strong moral argument against it.
"Fundamentally, war involves human suffering," Blank said.
Blank had no easy answers to offer listening students. She suggested a willingness to view the situation with nuance might be the place to start.
"We get tangled up, instead of having the more sophisticated, mature conversation that unfortunately seems to be absent from our political discourse these days," she said.
Watch Blank's full lecture here.