America is not in decline and has an obligation to engage in foreign affairs, according to Dr. Robert Kagan ’80.

Kagan, a senior fellow at the Brookings Institution and co-founder of the Project for the New American Century, addressed Yale students on Monday as a speaker under the William F. Buckley, Jr. Program. His talk, entitled “America’s Role in the World,” examined the reasons for American intervention historically and argued that America should continue playing an active role in international affairs.

“I’m not here to claim that America is this wonderful nation of great virtue that constantly sought to bring wonderful happiness and security to the rest of the world,” Kagan said. “But rather that the United States has a variety of advantages that allow it to maintain power and stability.”

Kagan said the United States created the post-World War II world order and added that the United States’ willingness to use military power helps keep “the international system” in its current state.

He identified three major benefits of America’s superpower status during the last half-century: global prosperity, the spread of democratic government and the prevention of another world war.

Kagan said the global gross domestic product has more than doubled since 1950 and cited Paul Collier’s book, “The Bottom Billion: Why the Poorest Countries are Failing and What Can Be Done About It,” which estimates that about four billion fewer people are living in poverty in the post World War II age compared with the era before.

“The United States created an environment in which this could occur,” Kagan said. “The free market trade … made it possible for this amazing revolution in the global economy to take place.”

Before 1900, Kagan said there were roughly five democracies in the world. He added that following World War I there were around two dozen, although the rise of fascism turned some back. Today, there are 115.

The United States has also helped prevent large-scale conflicts like the two World Wars or even the Franco-Prussian War of the 1870s, he said.

Though many experts and laypeople alike seem to agree that the United States is in a state of decline, Kagan said this is not the case.

“We have to ask ourselves, compared to when?” he said. “The fact is, foreign policy is always hard. You lose more often than you win. You fail more often than you succeed in the best of circumstances.”

Kagan said American foreign policy has always had its failures and pointed to policies towards Asia in the 1950s as evidence.

Despite the economic recession, Kagan said that the United States still possesses 21 percent of the global GDP and still has the most powerful military in the world.

“The question is not whether or not we have the capacity to maintain [world supremacy],” he said, “But whether we have the will.”

Students interviewed said that Kagan executed his speech well and raised “thought-provoking” arguments.

McKenna Keyes ’14, a history major, said she found Kagan’s talk very relevant to the international and diplomatic history she has been studying. She added that she appreciated Kagan’s grounded historical references.

Harry Graver ’14, President of the Buckley Program, said that the group had been seeking a foreign policy speaker before contacting Kagan. Robert Kagan is the son of now-retired Yale classics professor Donald Kagan, a member of the Buckley Program’s board of directors.

“We felt there was something missing from campus discourse right now,” Graver said. “We were hoping to strike a contrast between what America’s role in the world is being treated as now and what it should be.”

Still, some students disagreed with Kagan’s standpoint on American exceptionalism.

While Keyes said she agreed that the United States is the strongest world power in today’s world, she said she would have liked to know how the U.S. could slightly lessen its responsibilities and partner with other countries and international organizations.

“The U.S. can’t keep world order by itself,” Kayes said. “It can’t always act on its own without the support of other countries.”

One of Kagan’s five books, “The World America Made,” was mentioned in President Barack Obama’s 2012 State of the Union address.