In recent days, Donald Trump has given a series of in-depth interviews shedding some light on what he means by the policy he calls "America First." The interviews are giving a clearer picture of the Republican presidential hopeful's approach to foreign policy.
Here are four things to know about Donald Trump's foreign policy:
1. It's unpredictable ... by design
Reporters covering Donald Trump never know what he'll say or do next. And that's the way he likes it. Trump thinks it's an advantage for the United States to keep foreign leaders guessing.
"I always say we have to be unpredictable," Trump told the Washington Post editorial board. "We're totally predictable. And predictable is bad."
Trump has spoken highly of Russian President Vladimir Putin, who also likes to confound expectations. Putin's invasion of Crimea and his recent military intervention in Syria both took international observers by surprise. That can be an important element of military success. Trump, for instance, refused to rule out the use of nuclear weapons in battling ISIS in Europe or the Middle East.
"I would never take any of my cards off the table," Trump said in a town hall meeting on MSNBC.
But critics warn the approach can be taken too far.
"The unpredictability shifts into unreliability. Then you pay a high price for that," says Peter Feaver, who worked for the National Security Council under George W. Bush and Bill Clinton.
"We could become untrustworthy," Feaver says. "And we would squander what has been the United States' great advantage over the last 25 years, which is while other countries complain about the United States, they basically prefer the United States to be the global leader than any other possible candidate."
2. It's all about the deal
Speaking to a pro-Israel group, Trump likened talks with the Palestinians to the kind of business negotiation he's famous for.
"I know about deal-making," Trump said. "That's what I do. I wrote The Art of the Deal."
Indeed, reporters from The New York Times who conducted a lengthy interview about foreign policy with Trump concluded that he approaches "almost every current international conflict through the prism of a negotiation."
For the most part, Trump thinks the United States has been getting the bad end of the bargain.
"You look at what the world is doing to us at every level, whether it's militarily or in trade or so many other levels, the world is taking advantage of the United States," Trump told CNN. "And it's driving us into literally being a third-world nation."
It's not surprising that someone who built his business fortune through deal-making would lean on that experience in foreign affairs. But critics say Trump is short-sighted in approaching each encounter as a zero-sum game, where a gain for China, for example, is automatically a loss for the United States.
"He fails to realize that there are a lot of win-win agreements in the world," says Daniel Drezner of the Fletcher School of Law and Diplomacy. "By threatening to drive harder bargains, he might manage to eke out a slightly larger share of the pie. But he also threatens to blow up that pie in the process."
3. There's more overlap than you might think with President Obama
Some of Trump's foreign policy pronouncements have a familiar ring, although he tends to say loudly what others only whisper.
"You have countries in NATO that are getting a free ride," Trump complained on CNN. "It's very unfair. The United States cannot afford to be the policeman of the world anymore, folks. We have to rebuild our own country."
President Obama and his defense secretaries have also pressed NATO members to spend more on their own defense. And Obama has complained that countries in the Middle East are all too willing to have the U.S. fight their battles for them.
"Perhaps most surprisingly is the extent to which [Trump] overlaps with some of President Obama's positions," Feaver says. "Where there's a sharp difference, of course, is that President Obama wanted to do less in the Middle East in order to do more in Asia. And Trump is talking about doing less in the Middle East and less in Asia."
Indeed, Trump has threatened to withdraw U.S. forces from Japan and South Korea, unless those countries agree to cover a much larger share of the cost.
4. Critics say he's ill-informed
Trump has recently named a handful of his foreign policy advisers, but insists he also keeps his own counsel. "I understand this stuff," Trump told CNN. "I mean, I really do understand this stuff."
Many foreign policy practitioners disagree. More than 100 Republican national security experts signed an open letter challenging Trump's policy positions and his competence.
One of them, Max Boot of the Council on Foreign Relations, warned in a separate essay that the billionaire businessman is "singularly unqualifed to be commander in chief."
"It's just a stunning degree of ignorance this guy has," says Drezner, another signer. "Fifteen years ago, people were talking about whether George W. Bush knew enough about foreign policy when he became president. George W. Bush is George Kennan compared to Donald Trump," he said, referring to the scholarly Cold War diplomat.
Even the name Trump has given to his brand of foreign policy alarms some observers. Trump has embraced the label "America First," a slogan that was also used by isolationists in the ill-fated effort to keep America out of World War II.