Amid the cacophony of campaign riffs and post-election tweets, two central themes have emerged as apparent pillars of Donald Trump’s foreign policy vision: ending Islamist terrorism and constraining China.

In some ways, Trump is not so different from modern presidential predecessors whose early ambitions were focused on a few big ideas in response to the world as they saw it.

Ronald Reagan wanted to defeat the “evil empire” of Soviet communism, promote capitalist democracy and reinvigorate U.S. global dominance. Bill Clinton sought to reposition the United States for the age of globalization and maintain leadership of strong international alliances. Barack Obama promised to take the country off a “perpetual war footing,” seek normal relations with old adversaries and work with global partners on big issues, such as climate change.

But in other ways, Trump is like nothing in recent memory. It remains unclear whether the president-elect and his team — few of whom have government foreign policy experience — see his individual policy pronouncements as part of a broader strategy or have begun to consider some of the contradictions they pose.

[How a week of Trump tweets stoked anxiety, moved markets and altered plans]

Trump has called for expanding the U.S. nuclear arsenal — saying, “let it be an arms race” — while urging improved relations with Russia, the United States’ principal nuclear adversary. He has said, without explanation, that North Korean development of nuclear-armed, long-range missiles “won’t happen,” and has blamed China for failing to prevent it while bleeding the American economy. He has not explained how the 4 percent U.S. growth rate he has predicted can be achieved at the same time as the potential trade war his policies could trigger with China, the third-largest U.S. trading partner and largest creditor.

Trump has said he will establish safe zones in Syria, presumably protecting those under fire from Syrian government and Russian bombing, while suggesting he would abandon aid for the rebels and cooperate with Russia against the Islamic State, in addition to pressuring Iran, Russia’s ally in Syria.

Trump congratulated Russian President Vladi­mir Putin for disdaining President Obama’s hacking sanctions and tweeted with apparent glee that the “Russians are playing [the U.S. news media] for such fools . . . funny to watch.” He has called on the world to “fight back” against the “religious threat” of terrorism, claimed credit for predicting terrorist attacks by refugees, and said the U.S. intelligence community is incompetent and politically biased.

“We have never had a populist movement or political insurgency that has actually won the White House,” said Stephen Hadley, national security adviser to former president George W. Bush. “We have it now, and it’s different.”

Hadley said he counsels concerned Americans and foreigners not to “overreact to noise in the system. Have some strategic patience, give them time to get their sea legs. . . . there will be time enough to criticize.”

Trump Doctrine

The first indication of a Trump Doctrine, if such a thing yet exists, may come this week with confirmation hearings for his national security nominees, none of whom has spoken publicly about any pending issues.

Among the several challenges that will require the Trump team to hit the ground running is North Korea, which conducted its fifth nuclear test, its largest ever, in September. In a New Year’s speech, leader Kim Jong Un said his country was in the “last stage” of preparations to test-fire a long-range missile capable of carrying a nuclear warhead to the continental United States.

Six-party denuclearization talks with regional partners and North Korea have been suspended since 2008, and the Obama administration has said it would not restart them until Pyongyang abandoned its nuclear program.

U.S. and European sanctions against Russia over Ukraine will have to be renewed before midyear, and Trump, as well as his nominee for secretary of state, Rex Tillerson, have indicated they are not fans. The pro-Western government in Kiev fears that Trump will use Ukraine as a bargaining tool to achieve the improvement of relations with Moscow the president-elect has said he seeks. Trump also has suggested that he is less concerned than Obama and U.S. allies have been with regard to forcing Russia to give up the Ukrainian Black Sea peninsula of Crimea, which Moscow invaded and annexed in 2014.

Trump also may face early decisions on a host of what are currently considered secondary issues, from Venezuela to Libya. He has indicated that he favors major revisions to Obama’s policy on Cuba and has left open his views on the U.S. commitment to NATO.

Then there is the sudden crisis. “They could walk into a major terrorist attack,” said defense expert Eliot Cohen, who helped orchestrate an anti-Trump letter signed by scores of foreign- and defense-policy notables during the campaign.

For those who see a strategy, virtually every issue the administration is likely to confront will be interpreted as a subset of the two main goals of fighting Islamist terrorism and recapturing economic dominance perceived as lost to the Chinese.

“I’m not of the view that Trump is operating by the seat of his pants, without a kind of foreign policy vision,” said Mark Dubowitz, executive director of the Foundation for Defense of Democracies. Beyond counterterrorism, “a rising China is both a national security and economic threat. Trump’s perceived closeness or sort of unfathomable comments on Russia are actually part of a deliberate strategy,” Dubowitz said.

Trump “believes in a strategic approach with Russia, not on core interests but where our core interests are more closely aligned — where Russia would be a helpful partner in confronting radical Islam and constraining the rise of Chinese power,” Dubowitz said.

Still, he said, Trump is “going to operate under what we used to call the FUD principle — create fear, uncertainty and doubt. I’m calling the emerging Trump Doctrine the FUD Doctrine.”

Power centers

Trump, like other modern presidents, is expected to put his own stamp on the decision-making structure, with a written document outlining the hierarchy of authority in the White House and with the major agencies expected to be issued during the administration’s first weeks. Traditionally, that document sets up the relationship between national security departments and agency heads, and their seconds and thirds. It outlines the duties of the national security adviser and delineates whether certain issues will be handled in the White House or at the agency level, extending even to who will chair certain meetings.

The answers to those questions have been both decisive and divisive in the past. President George W. Bush vetoed a play by his vice president, Richard B. Cheney, to chair the “principals’ meetings” of top officials in the president’s absence, insisting that they be led by his first-term national security adviser, Condoleezza Rice.

Obama, in his first national security directive, centralized decision-making in the White House, directing that third-tier policy committees across national security agencies be chaired by an NSC official, rather than giving a designated department the lead role.

[How the Obama White House runs foreign policy]

Clinton set up the National Economic Council (NEC) because, “in a different era, he wanted to give economics more importance in foreign policy,” said James Mann of the School of Advanced International Studies at Johns Hopkins University. Mann has written several books on national security organization.

While Obama folded the Bush-created Homeland Security Council (HSC) into the NSC, his first counterterrorism adviser, current CIA Director John Brennan, was given broad leeway and access to the president.

So far, Trump has created a structure that, depending on one’s perspective, seems designed for either diffused authority or conflict. In addition to the NSC, to be headed by retired Lt. Gen. Michael T. Flynn, he has revived the HSC, retained the NEC and created a new National Trade Council — all of whose leaders apparently will report directly to the president.

A wide range of national security experts with experience in government, all of whom asked for anonymity in anticipating initial chaos in the new administration, predicted clashes not only within the White House but between Flynn — most of whose experience is in counterterrorism — and James N. Mattis, the nominee to be defense secretary, as well as Tillerson. The experts also expect early departures.

The multiple national security power centers within the White House alone indicate a large number of staffers, although the Trump transition has indicated a desire to streamline the NSC.

Congress also has mandated an NSC policy staff of no more than 200. Under Obama, it ballooned to more than more than 400, more than half in policy positions and the rest in technology support and administration. Over the past two years, however, national security adviser Susan E. Rice has cut the policy staff to about 180, according to administration officials.