The question of America's role in the world is central to U.S. foreign policy, and we have debated it since the nation’s founding. Russia’s war against Ukraine has brought new urgency to the question.

The United States has rightly taken a leading role in responding to Russia’s invasion with economic sanctions and other measures. We are providing humanitarian and military aid to Ukraine and welcoming Ukrainian refugees. Importantly, we are working together with allies, especially the NATO alliance.

These actions have broad public support. While some Americans worry about a larger conflict with a nuclear-armed Russia, many think we should be doing more to help. In general, the American people agree the U.S. should be a leader in the effort.

Apart from responding to crises like Ukraine, however, Americans often disagree about what our role in the world should be. We have had serious, impassioned debates about this matter throughout our history, and our answers have evolved. Circumstances changed, and our beliefs and policies changed with them.

As I’ve noted before, you can get a sense of this from statements made by our presidents. George Washington said the United States should have commercial relationships with other countries but “as little political connection as possible.” Thomas Jefferson called for peace and commerce with all nations but “entangling alliances with none.” John Quincy Adams expanded trade agreements but declared that America “goes not abroad in search of monsters to destroy.”

By the 20th century, the monsters couldn’t be ignored. Woodrow Wilson said the U.S. would enter World War I for the world to “be made safe for democracy.” Franklin Roosevelt, gearing up for World War II, said the U.S. would be “an arsenal of democracy.” Ambitious claims about America’s role continued through the Cold War. John F. Kennedy said America would “pay any price, bear any burden, meet any hardship… to ensure the survival and success of liberty." Bill Clinton said America "stands alone as the indispensable nation." George W. Bush said our objective should be "ending tyranny in our world."

We haven’t always lived up to our high ideals and ambitious goals, however, and foreign policy failures have diminished Americans’ appetite for intervention. Vietnam came to be seen by many as a mistake. In Iraq, we quickly ousted Saddam Hussein, but stable government was elusive. Our 20-year engagement in Afghanistan ended as it started: with the Taliban in control.

Exercising world leadership isn’t easy or cheap, and the American people have a huge stake in the decisions we make, because they will pay the price: in dollars spent and, sometimes, in lives lost, as those conflicts demonstrated.

The United States is the world’s economic, military and cultural leader, and that preeminence is the reason we have these debates about America’s role. Our power may not be unchallenged as it was after the fall of the Soviet Union – China’s influence is growing – but we still shape the global order more than any other country. The world looks to us to lead. I have attended many high-level international meetings over the years, and I was always struck by how other nations looked to the U.S. for leadership, especially in times of crisis.

We obviously can’t solve all the world’s problems. We need to always center American interests and act in accordance with American values; and it’s essential that we work our allies, not unilaterally.

But the crisis in Ukraine has brought home that the world needs leadership, and the United States is uniquely positioned to provide it. We can’t avoid the role of world leadership, and we shouldn’t want to.

Hamilton Lugar School of Global and International Studies