The U.S. has been the world’s leader for decades in promoting democracy, political liberalization, free trade and collective security. For the most part, Americans support that role, but many are wondering about its costs, and are growing ambivalent about our global engagement.

We have sometimes acted unilaterally, but by and large over the decades, we have shown a preference for working with other like-minded countries to achieve our common goals.

We have certainly been in the forefront in support of multinational institutions dedicated to global security, including the United Nations, NATO and the World Trade Organization.

Our global leadership is apparent in science, technology and education. We invest heavily in these areas. We award the most doctoral degrees and have renowned universities, which are centers of research and attract many of the world’s finest students. Our millennial generation is the best educated in the country’s history, with 40% earning college degrees.

But our leadership has always faced challenges. Many of us remember the Cold War and our leadership in the fight to stop the spread of communism, which lasted 50 years. Today we’ve entered a new phase of domestic challenges, among them, an aging population, a shrinking middle class, political dysfunction, rising income inequality, a tattered social safety net—all seem to threaten our future.

In addition, we face foreign policy challenges from rising powers like China, hostile actors like Russia and rogue states like Iran and North Korea. They contest our primacy by building up their militaries, opposing our interests, intruding in other countries’ affairs and developing nuclear capabilities.

Even our allies provide challenges. Our European friends have undertaken greater economic and political integration, moved away from a close embrace of the U.S., turned to former communist states in Eastern and Central Europe, adopted a common currency and taken steps toward joint military forces.

There are natural challenges too, like climate change. Rising sea levels could displace millions of Americans from coastal areas, and alter the character of geographic regions. Much of our population is in the path of hurricanes and increasingly frequent tropical storms.

Many of us wonder how to respond to these various and formidable challenges. We value our nation’s identity as a premier economic, financial and military power, but see the US becoming less influential and less respected, as China, Russia, North Korea and others emerge to dispute our leadership. We want to avoid confrontation, but do not want to be pushed around either.

In this uncertain and dangerous world, we favor strengthening our national defense and wonder whether we should reduce our international engagement and let other counties step up to their own problems.

With his slogan of “America First,” President Donald Trump has steered the U.S. toward a more unilateral approach to these challenges. His approach creates doubts about our leadership, with many of our allies seeing us as less reliable than we once were. If that perception grows, the strength and effectiveness of our global leadership will diminish.

My point is that as the Chinese and Russian models of authoritarian leadership and centralized economies emerge, we must put aside our doubts, embrace our traditional values and leadership role, and let the world know that U.S. global leadership is back.

If we do, the world will be a safer and better place.

Lee Hamilton is a Senior Advisor for the Indiana University Center on Representative Government; a Distinguished Scholar at the IU Hamilton Lugar School of Global and International Studies; and a Professor of Practice at the IU O’Neill School of Public and Environmental Affairs. He was a member of the U.S. House of Representatives for 34 years.