WASHINGTON — Is Bernie Sanders a closet foreign policy “realist?” Reading his few pronouncements on foreign policy, you sense that he embraces the realists’ deep skepticism about American military intervention. But he has said so little about foreign policy that it’s hard to be sure.

Foreign policy is the hole in Sanders’ political donut. We know what he doesn’t like — the 2003 invasion of Iraq, which he mentions, in nearly every debate, almost robotically, describing it as “one of the worst foreign policy blunders in the modern history of the United States.” But there’s far less clarity about what he does favor.

“I fully concede that Secretary (Hillary) Clinton, who was secretary of state for four years, has more experience — that is not arguable. But experience is not the only point, judgment is,” Sanders said in a Feb. 4 debate before his big New Hampshire win.

Now that Sanders has nearly tied Clinton in Iowa and won New Hampshire, there’s a real possibility that he may emerge as the Democratic nominee. And the question is: How scared should mainstream Democrats be about Sanders as a foreign policy president?

It’s hard to know. Sanders is running a populist campaign that centers on economic justice. Foreign policy is an afterthought. If I had to guess, I’d say that Sanders would continue — and reinforce — President Obama’s wary approach to using force, whereas Clinton would be more hawkish.

But that’s just a guess. Perhaps Sanders would be far more dovish. Clearly, if he wants to be taken seriously as his party’s potential nominee, Sanders needs to explain how he would behave as commander in chief. The nation is at war against a terrorist adversary. How would Sanders lead?

Sanders’ statements on Syria suggest that he would take a position embraced by many self-described realists. His first priority, he says, would be a “broad coalition, including Russia” to defeat the Islamic State. “Our second priority must be getting rid of (President Bashar Assad), through some political settlement, working with Iran, working with Russia.”

Some critics would argue that it’s immoral to make replacing a leader who used chemical weapons a secondary concern. But Sanders’ defenders could argue that foreign policy is about making clear choices, especially when they aren’t easy.

Foreign policy just hasn’t been on Sanders’ radar: His campaign website lists 22 important issues. “Income and wealth inequality” is at the top, and 19 are about domestic policy. Just three involve foreign concerns, and one of these is climate change, which Sanders has described as the biggest threat to national security.

Unease about Sanders partly reflects the fact that he seems to have no real foreign policy mentors. The Sanders campaign made comical missteps the past few weeks when it tried to name his key foreign policy advisers. Several of them said they had just briefed the candidate once or twice; one was a full-time White House staffer.

In Sanders’ speeches, and comments in the last five televised debates, his foreign policy views are vague, but not all that different from those of a Democratic electorate that is skeptical about U.S. military power and insistent that other countries do more fighting. His views do, however, mark a sharp break with the centrist foreign policy view that the U.S. needs to be more assertive in projecting power after the Obama years.

Pressed about his foreign policy views, Sanders often cites a November speech he gave at Georgetown in which, among other things, he embraced the label “democratic socialist.” That speech laid out a policy “to destroy the brutal and barbaric (Islamic State group) regime. ... But we cannot — and should not — do it alone.” He cited a standard liberal list of failed U.S. military interventions, in Iran in 1953, Guatemala in 1954 and Chile in 1973.

Sanders needs to answer a range of foreign policy questions: Would he enforce navigation in the South China Sea, even if it meant possible confrontation with China? How would he combat Russian aggression in Ukraine?

In that Georgetown speech, Sanders evoked President Franklin D. Roosevelt and his argument, in Sanders’ words, that “real freedom must include economic security.” Which raises the question: What does Sanders think of the FDR who, as commander during World War II, astonished his aides by insisting that “unconditional surrender” of Germany and Japan was the requirement for victory?

One can imagine a President Hillary Clinton making such a harsh demand. But what about a President Bernie Sanders?

By David Ignatius 

David Ignatius’ email address is davidignatius@washpost.com. — Ed.

(Washington Post Writers Group)