Society & Culture

Defense treaties affect support of military action

When Americans are told the U.S. has a defense treaty with a foreign country, they're more supportive of military action and more tolerant of civilian and military deaths. (Getty Images)

Public cites moral obligation to keep promises, even if it costs lives

With tensions continuing to grow between Ukraine and Russia, the United States is sending thousands of troops abroad to bolster its NATO allies against the threat.

But Ukraine isn’t a member of NATO, and President Joe Biden said he won’t send troops to the besieged country. There’s likely a very specific reason for that.

New research from the University of Georgia suggests Americans are more supportive of military action in foreign countries when the U.S. has existing defense treaties with those nations. The U.S. doesn’t have such an arrangement with Ukraine, so it would probably be difficult to drum up support for military action to defend the nation.

Jeffrey Berejikian

“What the United States is doing makes perfect sense to me, given what we found in our study,” said Jeffrey Berejikian, corresponding author of the study and a Josiah Meigs Distinguished Teaching Professor in the School of Public and International Affairs.

“When Russia first invaded Ukraine, President Obama said the red line is NATO, where we have an alliance. We will defend NATO. Biden has been very clear to articulate the same thing. There just isn’t any way to get public support behind the idea without an alliance in place.”

Defense treaties influence tolerance of civilian, military deaths

 Published in Contemporary Security Policy, the study found that Americans are more likely to support military action when reminded of international commitments. They’re also more tolerant of both civilian casualties in the invading country and U.S. military deaths.

If you see political leaders being very specific about American legal obligations to NATO, Japan or South Korea, they’re probably trying to shift public opinion in support of that policy.” —Jeffrey Berejikian, Josiah Meigs Distinguished Teaching Professor

Political leaders are sometimes vague when they discuss the need for military action, often saying that a drone strike or something similar is in the interest of national security, Berejikian said. But other times, they are really specific, citing international agreements down to the chapter and article where they appear.

“What we found is that depending on how you frame a problem, you can drive public opinion,” said Berejikian, who is also a senior Fellow with the Center for International Trade and Security. “If you see political leaders being very specific about American legal obligations to NATO, Japan or South Korea, they’re probably trying to shift public opinion in support of that policy.

“It doesn’t mean that they want to go to war. But it might mean that they think we may have to.”

A moral obligation to defend U.S. allies

The study consisted of two surveys of more than 1,500 people each.

In the first survey, the nationally representative group of people were told about a potential military crisis between North and South Korea. Half of the participants were told about America’s alliance with South Korea. The others were not.

The researchers found that those who were told about the defense treaty were more supportive of military action to protect South Korea. The biggest effect was on people who identified as political independents.

It turns out that when you remind the public of a prior alliance commitment, the public thinks that we’re morally bound to live up to our word.” —Jeffrey Berejikian

The second experiment was structured the same as the first, but the researchers provided more specific information about the treaty, citing the portion that obligates the U.S. to protect South Korea if the country is attacked.

When provided with more detailed information about the treaty, participants of all political affiliations were more supportive of military action. And they were more accepting of potential casualties—both of Korean civilians and U.S. military personnel.

“It turns out that when you remind the public of a prior alliance commitment, the public thinks that we’re morally bound to live up to our word,” Berejikian said. “The other reason for supporting military action was a more practical concern: If the U.S. makes a promise and then breaks it, our reputation will be damaged.”

This perspective is particularly relevant to the Ukraine crisis.

“In some ways, you’re enhancing the credibility of your willingness to go to war when it’s important to you if you say, ‘Here’s where we’ll stand and here’s where we won’t,’” Berejikian said. “I think that’s where we are: providing support in a way that doesn’t undermine our promise to NATO by overpromising to countries that don’t have an alliance with us.”

The study was co-authored by Florian Justwan, a doctoral graduate from the School of Public and International Affairs who is now an associate professor at the University of Idaho.