The tragic killing of Chris Stevens (the U.S. ambassador to Libya), and the anti-American protests and violence in the Arab world and beyond, have raised a towering question: What will be the foreign policy of the next president?

The answer will have enormous impacts on Americans, but the issues can be confusing. Part of the reason is that the partisan philosophies that imprint most domestic issues do not easily apply to foreign policy. Here's a bewildering tidbit for domestic-policy wonks that further complicates the matter: Major approaches to foreign policy find influential advocates in both parties.

President Obama's views are hardly a secret. He is best described, based on four years of foreign policymaking, as a "liberal internationalist," characterized by a commitment to a rules-based international system with strong multilateral organizations, but also by a reluctance to act unilaterally in international affairs. The 2011 Libyan intervention is a case in point: Obama supported the use of military forces to save lives, but probably would not have done so without Arab League endorsement and U.N. Security Council authorization.

At the same time, and much to the consternation of some human-rights activists from both the Democratic and Republican parties, he has been skeptical about ambitious moral objectives for U.S. foreign policy, such as exporting democracy.

This tilt toward a traditional foreign-policy realism that defines security interests more narrowly is also evident in Obama's willingness to part with some members of his party and use drones to target Al-Qaida leaders, even if they are U.S. citizens.

The Obama worldview gives us a sense of how he'd respond to any number of current and future challenges. For instance, on Iranian efforts to build a nuclear weapon, Obama would be unlikely to attack Iranian facilities and go to war without strong multilateral support, and he would continue to exercise strong pressure on Israel not to act unilaterally. Even in the event of an international armed conflict with Iran, Obama would be very reluctant to pursue the ambitious regime change and nation-building effort that characterized U.S. engagement in Iraq.

Mitt Romney's worldviews aren't so clear.

While he has called for an American century of freedom, peace and prosperity and has accused Obama of not being tough enough on Iran and being too tough on Israel, his statements reveal little about underlying national-security perspectives that would enable us to predict his responses to future crises. And the matter is further confused by the fact that his closest foreign-policy advisers have radically differing views.

Robert Zoellick, the former World Bank president who has been named as head of Romney's national-security transition team, comes from the traditional realist wing of the Republican Party's foreign-policy establishment. Informed by Zoellick's perspectives, a Romney foreign policy toward Iran, China or Israel would not differ dramatically from what we might see in a second Obama administration.

On the other hand, most of the individuals who have been identified as key potential foreign-policy advisers around a President Romney see the world very differently than Zoellick does. Some, like former ambassador John Bolton, are Hobbesians, who believe the United States must act as an all-powerful Leviathan to respond to security threats in an international arena that philosopher Thomas Hobbes characterized as a "war of all against all."

Others, like Dan Senor, who served the Bush administration in Iraq, are neoconservatives, informed by a deep commitment to American exceptionalism and prepared to assert American civilian and military power to promote democracy. Both groups have often dismissed the role of international institutions and are comfortable with the unilateral application of U.S. military force.

If these latter advisers hold sway in a Romney administration, as they did under George W. Bush prior to the Iraq war, a Romney foreign policy will differ radically from the foreign policies of the past four years. In Iran, in North Korea, and in other crises yet to unfold, the United States will be much more likely to move on its own to deploy troops, with broad ambitions to pursue regime change and nation-building.

The stakes are huge, and Americans deserve to know that kind of foreign policies they are choosing when they cast their vote for president. The upcoming debates will provide Americans with the opportunity to scrutinize Obama's decisions and their implications for the future. More importantly, they will give Romney the chance to clarify just where he stands on critical issues of war and peace.

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Eric P. Schwartz is dean of the Humphrey School of Public Affairs at the University of Minnesota. He served as U.S. assistant secretary of state for population, refugees and migration between 2009 and 2011, and as special assistant to the president for national security affairs during the administration of Bill Clinton. Lawrence R. Jacobs is the Walter F. and Joan Mondale Chair for Political Studies and is the director of the Center for the Study of Politics and Governance at the Humphrey School and the Department of Political Science at the University of Minnesota.