Two military policy experts clashed over what role the United States military should take on the global stage at a Thursday afternoon talk.

Christopher Preble, vice president for defense and foreign policy studies at the Washington, D.C.-based Cato Institute, and Thomas Donnelly, director of the Washington, D.C.-based think tank Center for Defense Studies, debated their viewpoints on military power in front of about 20 students in William L. Harkness Hall. Preble criticized what he said was an aggressive foreign policy taken by the United States in recent decades, while Donnelly defended the nation’s interventionism.

Preble argued that the United States is currently pursuing a military policy that is more aggressive than it needs to be. The government spends $800 billion annually on defense, a figure that Preble said makes up nearly half of defense spending worldwide and is evidence of a freeloading problem in global defense.

“Our allies consistently spend far less than we do on defense spending, and for one reason,” he said. “When you buy someone a house, they’re not inclined to pay for it. When we buy them security, they’re not inclined to pay for it.”

Donnelly, who supports a more interventionist military policy, countered that the United States has always taken an interest in the international balance of power, especially among its allies in Europe.

The U.S. military sometimes intervenes in regions not because it faces a direct threat, but because involvement will impact global security, Donnelly said. America’s “burden-bearing” comes at a high cost, but is worthwhile, he said.

“There’s unlikely to be a great power war in Europe in your lifetimes,” Donnelly said. “Though that’s a result of a hundred years worth of American effort and blood, the outcome is worth it.”

But Preble said the United States’ military involvements have strained its already weak economy, though he added that the U.S. military budget is unlikely to drive the nation to bankruptcy.

U.S. interventionism has resulted from politicians in Washington making promises they cannot keep, and the United States fighting wars “just because it can,” Preble said. He noted that the United States has engaged in military action more times in the past 15 years than it did during the 45-year duration of the cold war.

“It’s going to be more and more draining on the United States as its allies grow weaker and weaker,” Preble said.

Still, Donnelly said the United States’ most important allies are generally willing to fight alongside it, so long as the United States remains a “reliable partner” in their eyes. While the United States does occasionally fight wars “because it can,” Donnelly said the United States often engages in other conflicts with global implications. He cited U.S. military involvement in the Middle East as an example, noting that the region’s energy resources and political instability make its problems “not easily containable.”

Preble said he would rather see the United States promote democratic values and economic order in a peaceful manner, which he said the United States often does effectively. War should always be a last resort, he said.

After Preble and Donnelly finished debating, they answered students’ questions on issues ranging from the United States’ role as an “enforcer” to how the United States should respond if Iran were to attack Israel with nuclear weapons.

The event was hosted by the William F. Buckley, Jr. Program and the Rosenkranz Foundation.