Recent presidential campaigns have not focused on foreign policy. This year could be different. The volatility of the international system has increasingly become intertwined with the domestic issues that tend to dominate presidential elections.

The civil war within Islam has produced the worst international terrorist threat of the modern era: ISIS, or Daesh. This conflict, as well as instability in Africa, has already pushed millions of migrants into Europe, which has given rise to greater nationalism and threatens the European project. Increasing terrorist attacks in the West—including the United States—call into question current counterterrorism strategies.

At the same time, slow growth and economic dislocation is producing a backlash against globalization. And against the backdrop of economic stagnation, isolationist sentiments in America are hitting levels unseen since the immediate post-Vietnam era.

Most significant, a major presidential candidate is challenging fundamental assumptions about U.S. foreign policy. Consensus behind a new grand strategy did not quite cohere after the Cold War. But presidential candidates since 1992, while differing on their approaches to specific issues, generally agreed that the U.S.-led postwar architecture should be preserved—and that American leadership was necessary to respond selectively to global crises and to keep the peace among major powers.

Donald Trump is different. Trump's pronouncements are more than an attack on Hillary Clinton’s worldview. Although stated in provocative and unorthodox ways, he takes issue with many of the tenets that have guided U.S. foreign policy across both Republican and Democratic administrations since the end of the Cold War. What we are witnessing is nothing less than the birth of a Trump Doctrine, one that calls for a break from the status quo on at least five main issues: U.S. goals, countering the terrorist group ISIS and Islamist extremism, democracy promotion, immigration and great-power relations.

U.S. Goals: Trump’s slogan—America First—harkens back to the isolationists of the pre-World War II era. Trump, however, is not an isolationist. Quite the contrary. He favors a large defense budget and wants to ensure that America remains the world’s sole military and economic superpower. Rather, “America First” is Trump’s way of attacking “globalism.” The term "globalism" encapsulates, for Trump, the myriad policies that he believes are expending American resources on behalf of goals incidental to core U.S. interests.

It is in the realm of international economics in particular that Trump is sounding the alarm of globalism. U.S. presidents since the end of World War II have taken the view that economic integration and free trade are win-win propositions that both further global security and benefit American interests, foreign and domestic. Trump’s America First view is more zero-sum and nationalistic. He believes that the United States naively practices free trade while other countries gain undue advantage through mercantilist practices. He believes many trade agreements have damaged America—negatively affecting U.S. workers and the middle class by facilitating movement of manufacturing jobs from the United States to other countries such as China and Mexico. He believes that these and related policies are producing slow economic growth, huge debt and undermining the underpinnings of U.S economic power.

Trump is intent on prioritizing U.S. economic interests. He, for example, will renegotiate NAFTA and abandon the current text of the Trans-Pacific Partnership in order to reassert U.S. sovereignty and protect and expand U.S. manufacturing and employment.

Countering ISIS and Islamic Extremism: Trump appears to see the threat of ISIS and Islamist extremism as urgent and the principal current threat to the United States. He believes that President Obama and candidate Clinton fail to recognize the nature of the problem—that ISIS and al-Qaida are Islamist terrorist groups—and accept that we have to live with the threat is unacceptable. He has said that a Trump administration will seek to defeat ISIS quickly and to eliminate its threat to the United States, rejecting the notion that we should learn to live with the threat. He wants U.S. alliances to focus on the threat of Islamist terrorism and also is willing to cooperate with Russia to defeat it. He is willing to use more U.S. forces and to adopt more aggressive tactics. He appears to favor using a lot of force against terrorist targets in the Middle East but then get out rather than maintain a significant role on the ground for years. He also wants to review U.S. immigration and visa policy as well domestic law enforcement policies to deal with this threat.

Immigration: Trump also departs from the establishment on both legal and illegal immigration. He wants to break the cycle of millions of illegals becoming legalized every few decades in deals that include commitments to control illegal immigration—commitments that always go unfulfilled. His often used imagery of a wall expresses the determination to break that cycle by whatever means are necessary.

On legal immigration, it appears that Trump would like to reduce the flow and perhaps change the criteria for who would be admitted. He argues that reducing and changing criteria for legal immigration would result in increased employment for Americans and legal residents, particularly in the lower end of the income spectrum. His concerns about ISIS using flows of refugees to infiltrate terrorists into the United States led him to call for suspending visas for all Muslims until a process was established for reliable vetting, which later he modified to temporarily suspending admission of visitors and immigrants from terror-afflicted countries.

Trump appears to fear Europe’s problems replicating themselves in the United States. In Europe, the continent is in the midst of a potentially dangerous paradigm shift. According to some estimates, more than 700,000 Africans are waiting in Libya to move to Europe, with millions more likely to follow their path given population growth and economic and political crises on the continent. This could eventually dwarf the already destabilizing current and future flows from conflicts in the Middle East and South Asia. This would inevitably have huge impacts in domestic politics and security in Europe.

Great-Power Relations: Trump is envisioning a new era of great-power relations. He favors a less truculent approach to Russia than Hillary Clinton. While other presidents have pursued common understandings with Moscow, Trump envisions perhaps a more sweeping paradigm shift—and perhaps a new grand bargain: acceptance of some kind of a sphere of influence for Moscow in parts of its immediate neighborhood in exchange for Russian cooperation on issues important to the United States with regards to war on terror, Syria, and the Asian balance of power. In his view of Russia, he may be closer to President Franklin Delano Roosevelt’s attitude toward the Soviet Union than the approach of any subsequent American president.

Due to strong pressure from Trump campaign officials, for example, the Republican platform dropped an endorsement of the provision of lethal defensive arms and assistance to Ukraine. Trump’s recent statement that called into question America’s guarantee to NATO allies under Article V if they are not meeting their own defense obligations created a furor. Trump made it clear that he wants to use it as a bargaining tool to force allies to pay for their defense, and has also stated that he wants to preserve NATO.

With China, by contrast, the Trump Doctrine would pursue a much harder line. He has promised to place China’s economic practices—its alleged currency manipulation, lack of intellectual-property protections, and economic espionage—at the center of the bilateral relationship. Economic pressure, Trump believes, would not only address U.S. domestic concerns—such as the loss of manufacturing jobs—it would also provide a means by which Washington could elicit Chinese cooperation on security concerns such as the North Korean nuclear program.

Great-power relations may also shift in the context of U.S. relations with its traditional allies. Trump is hardly the first American political figure to gripe about our allies' free-riding. What distinguishes Trump, however, is the degree to which he is consumed with the issue. While U.S. presidents have tended to accept freeloading as a price worth paying for a network of alliances that underwrites international security and preserves U.S. global leadership, Trump is prepared to wield U.S. leverage to ensure that U.S. alliances pay their “fair share.”

Democracy Promotion: Particularly since the Reagan years, democracy promotion has become a central tenet of U.S. foreign policy. Policymakers have generally reached the conclusion that the spread of democracy and human rights is not only consistent with American ideals, but also contributes to a more peaceful world. When military operations in Afghanistan and Iraq were undertaken to overthrow regimes posing serious security problems, bipartisan coalitions supported the installation of democratic governments to reestablish political authority. The consensus was that democratic ideals have universal appeal and can take hold across countries and regions with different histories and cultures.

When Trump alludes to democracy promotion, he does so mostly in the context of his sharp attacks on nation-building and regime change. In his Republican National Convention speech, for example, he lambasted the U.S. decision to support the overthrow of dictatorships in Iraq, Libya, Egypt and Syria, arguing that these efforts undermined stability and U.S. counterterrorism priorities. Trump pledged unequivocally to “abandon the failed policy of nation building and regime change.”