In her 2014 book and in recent interviews, Hillary Clinton appears to be signaling her foreign-policy differences with the current president. Mocking his reported motto in an interview with the Atlantic, she remarked, “Great nations need organizing principles, and ‘Don’t do stupid stuff’ is not an organizing principle.” Since the end of the Cold War, establishing a clear principle around which to base a foreign-policy agenda has not proven easy. During the Cold War, the overriding challenge was the threat of Soviet expansion, and thus “containment” served as a central organizing principle. However, since then, the complexity and variety of policy challenges ranging from the rise of China to terrorism, climate change, energy security, nonproliferation and more have rendered it nearly impossible to establish a single organizing principle. Bill Clinton’s team underwent an exercise in 1993 dubbed the “Kennan sweepstakes” to see if it might establish a theme rivaling the containment strategy developed by George Kennan in the 1940s. The strategy of “engagement and enlargement,” which focused on leveraging Communism’s demise to expand the community of democracies, was attempted briefly as a slogan but never stuck, even though the basic premise underlay much of what the Clinton administration sought to promote. George W. Bush adopted the “war on terror” as his organizing principle, but it proved to be controversial and too narrow, given the other challenges facing the United States.

In 1994, Bill Clinton’s State Department was so eager to develop a clear phrase that it sought guidance directly from Kennan, by then in his nineties, who advised that they abandon their efforts to identify a new bumper sticker–style slogan. Try instead, he said, for a “thoughtful paragraph or two.” Twenty years later, we are still searching for that thoughtful paragraph.

ONE STRIKING difference between Bill Clinton and Barack Obama has been the emphasis the former placed on leading and positioning the Democratic Party as compared to the latter. One of Clinton’s primary objectives was to shift his party to the center of American politics, precisely so that Democrats could be successful on the national stage. Mindful of this objective, Clinton challenged labor unions at home, supported free trade, advocated for democracy promotion and eventually demonstrated a willingness to use force when necessary to protect vulnerable populations. His stance on trade illustrated that Democrats could align with the business community; fostering democracy promotion and a willingness to use force exhibited that Democrats could pursue a muscular national-security policy.

Obama has displayed much less interest in what his presidency might mean for the party in the long term. Hillary Clinton and the other Democratic candidates will have to decide whether this race is merely about themselves and their vision for their presidencies—or about the future of the Democratic Party.

In one important way, the next president should pledge to do what Obama mistakenly thought he had already accomplished: get the United States out of military engagement in Iraq. The United States has been involved militarily in Iraq under the last four administrations, and cannot afford to have its foreign policy consumed with that country as it has been since Saddam Hussein invaded Kuwait in August 1990: George H. W. Bush launched Operation Desert Storm; Bill Clinton patrolled no-fly zones and carried out selected bombings; George W. Bush invaded Iraq and toppled Saddam Hussein; and Obama, after ending the U.S. military operation his predecessor had initiated, now finds himself back in Iraq to fight the Islamic State.

The battle against the Islamic State revives several challenges that have persisted in Iraq for years. A Shia-led government is unwilling to ensure sufficient inclusion of Sunnis and Kurds to function effectively as a government for the entire country, and the divisive agendas of neighbors like Iran and Turkey further impede the potential for progress. The United States can cajole, but it cannot ensure that a more inclusive government emerges, and it can provide training to the Iraqi army, but its abilities to create an effective fighting force are limited. If Obama does hand off the Iraqi problem to his successor, as the three presidents preceding him did, the next president should not permit military involvement in Iraq to consume yet another four or eight years. Containing the terrorist threat from the region—not eliminating it—is the only realistic strategy.

A second goal, related to the first, should be to enhance the rebalance to Asia. This is a policy that should be central to Hillary Clinton’s campaign, since she and her team at the State Department were critical in launching it in the first place. Rebalancing does not mean that suddenly the United States would cease to retain any strategic interest in Europe and the Middle East; this would simply replace one expression of overbalanced foreign policy with another. For her inaugural trip as secretary of state in 2009, Clinton traveled to Asia, with Japan as the first stop. The next president should do the same. If the TPP is signed this year, the agreement will provide a major boost to the rebalancing effort, but more generally, the next president must continue to bolster traditional American allies (in particular Japan and South Korea), deter Chinese aggression and intimidation in the South China Sea, and continue to develop ties to ASEAN countries.

Looking beyond Asia, the Iranian nuclear issue may be resolved by this president; the Israeli-Palestinian conflict will remain on the agenda for the next. As long as Vladimir Putin remains in power, any future U.S. president will need to continue to contain the threat Russia poses to Europe. A formidable test for the next president will be to address those challenges that require other countries’ cooperation in a world in which the United States is no longer able to dictate to others. Today, central challenges requiring international collaboration include nonproliferation, terrorism, cybersecurity and climate change. Moreover, beyond basic questions of relations with particular powers (most notably China and Russia, but also India, Brazil and South Africa) looms the question of the centrality in American foreign policy of human rights and particularly the responsibility to protect populations at risk of genocide.

If the Democratic Party is to continue to serve as the progressive party in the United States, then the responsibility to protect must maintain a central position in the next Democratic president’s agenda. The international order is changing, and while the United States no longer dominates global affairs as it did in the 1990s, it remains the world’s leading power. We now understand that the United States cannot remake other societies. But we also understand that without U.S. leadership, a liberal international order cannot exist. When crimes against humanity are committed, only the United States can lead a coalition to stop the violence, and any Democratic candidate for president should support this foreign-policy priority.

Hillary Clinton’s foreign policy would likely be far more proactive than that of Obama—yet she cannot fully embrace the foreign-policy agenda of her husband, either, as circumstances have changed dramatically over time. Going forward, the United States will require a president who appreciates the limitations of U.S. power and yet still maintains the resolve to identify opportunities to lead the world.

James Goldgeier is dean of the School of International Service at American University. You can follow him on Twitter at @JimGoldgeier.