If there’s one thing we know about Bernie Sanders, he sure doesn’t like Henry Kissinger.

And if there’s one fact that he likes to deploy in his foreign policy case against Hillary Clinton, it’s her vote authorizing the Iraq War 14 years ago, when Clinton was just in her second year as a senator from New York.

But aside from the Kissinger snark and some minor back-and-forth over US policy in Cuba, foreign policy played only a little role in Wednesday night’s Democratic presidential debate, and it’s played an equally minor role throughout the entire contest. On one hand, that’s because the Sanders insurgency has zeroed in on income inequality, the growing wealth gap and the role of wealthy donors in campaign finance. But it’s also because Clinton, whether or not you trust her judgment, is the most qualified non-incumbent candidate in decades when it comes to international affairs. In addition to her service in the US senate, she also served for four years as secretary of state and eight years as first lady. It’s truly formidable.

Yet, given Clinton-Sanders dynamic, there’s still a lot of space for Sanders to make a strong foreign policy case against Clinton, and time after time, Sanders just hasn’t made that case. Maybe that’s politically wise; shifting his emphasis from Wall Street and income inequality would dilute his message with an attack based on issues that seem far less salient to Democratic primary voters.

But it’s true that Clinton’s foreign-policy instincts have always been more hawkish than those in her own party and, often, those of president Barack Obama and vice president Joe Biden (who, according to Jeffrey Goldberg’s amazing piece in The Atlantic about Obama’s world view, said Clinton ‘just wants to be Golda Meir’).

To some degree, the problem with challenging Clinton on foreign policy is that Sanders would largely be challenging the Obama administration, and that’s tricky when you’re trying to win the votes of an electorate that still adores Obama. But Sanders certainly hasn’t shied away from stating clear differences with the Obama administration’s approach to domestic policy.

Moreover, to the extent that Sanders made a clear and cogent case on international affairs, he could claim that his more dovish approach represents true continuity with the Obama administration (and that Clinton’s more hawkish approach shares more in common with a  potential Republican administration). There’s no doubt that Sanders is a talented politician; in one fell swoop, he could use foreign policy to drive a wedge between Clinton and the Obama legacy. That’s a very powerful tool, and it’s one that Sanders, so far, hasn’t been interested in wielding.

Fairly or unfairly, Sanders is tagged as a one-issue protest candidate, and he suffers from the perception that his candidacy’s purpose is to nudge Clinton further to the left, not to win the Oval Office. By adding a foreign policy element to his critique of the Democratic frontrunner, Sanders could bend a more skeptical media into taking him more seriously and show voters that he really can fill out what Americans expect from a president. In the 21st century, like it or not, the president is the chief policymaking official when it comes to foreign policy.

Given the stakes involved, it’s not too late for Sanders to make this case as the Democratic contest turns to larger states like Ohio, Illinois and Florida next week and, after that, Pennsylvania, New York, New Jersey and California. If he wanted to do so, there’s a long list of areas from which Sanders could choose.

Here are four of the most salient.

Syria

It’s clear that Clinton (unlike Obama and Biden) favored a far more interventionist approach to the Syrian civil war in 2011 and 2012 by arming so-called ‘moderate’ Sunni rebels who opposed Syrian president Bashar al-Assad. Clinton’s supporters claim that early support could have bolstered a mainstream Sunni force united against Assad.

But history shows us, from Iraq to Afghanistan to Yemen to Libya, any US support, including weapons, might have ended up in the hands of the far-more radical ISIS/Islamic State. There’s no guarantee that US support for moderate rebels would have stopped the rise of ISIS in Syria.

Sanders could point out that cooler heads in the Obama administration prevailed, hugging Obama the same way that Clinton has hugged Obama-era domestic policies like health care. The message is simple: Clinton’s instincts would have put US weapons in the hands of ISIS. Obama’s instincts — and those of Sanders — kept the United States out of the world’s nastiest quagmire.

Libya / Mali

Clinton, too, was among the most resolute supporters of the efforts to oust Muammar Gaddafi. Forget Benghazi, a partisan sideshow. Today, Libya is in Obama’s own words, a ‘shit show.’ Decades of Gaddafi rule centralized power in the ruling family’s hands, so Libya never developed truly national institutions uniting the country’s three disparate regions.

Moreover, after Clinton succeeded, with her French and British counterparts, in ousting Gaddafi, she showed little interest in helping the Libyan people build those institutions. That left a power vacuum that’s now being filled by local tribal leaders, would-be military strongmen like Khalifa Hifter and radical jihadists sympathetic to ISIS. Even worse, the Libyan chaos bled over the border into the Sahel region, fueling the civil war in Mali that destabilized northern Mali and required French intervention two years later.

The entire Sahel region, which contains some of sub-Saharan Africa’s poorest countries and which often brings together northern Muslims with southern Christians, remains a rich target for would-be radical jihadists. Again, Sanders could argue that Clinton’s instincts were wrong, portending a trigger-happy approach to foreign policy that failed to see what now seem like fairly obvious destabilizing consequences far beyond Libya’s borders.

Honduras

Sanders has attacked Clinton’s position in favor of turning back unaccompanied minors from Honduras, Guatemala and El Salvador that began arriving in waves at the US border in 2014.

But he hasn’t shown much interest in attacking the business-as-usual approach that Clinton took in 2009 when a military coup ousted Honduras’s elected president Manuel Zelaya. It’s true that Zelaya was trying to change the constitution to allow reelection. But the Obama administration fumbled over even calling the textbook military coup a ‘coup,’ and Clinton never forced Honduras, the coup leaders or Zelaya’s successors to pay a price for undermining democracy and the rule of law. Never mind that current right-wing president Juan Orlando Hernández has co-opted the Honduran constitutional court to allow his own reelection in 2017.

The ensuing seven years have marked a staggering rise in drug-related homicides, a corresponding hardline military response from Hernández and, most tragically of all, the kind of impunity that’s marked the assassinations of labor, environmental, LGBT and indigenous activists, most recently activist Berta Cáceres just last week.

If there’s one area where the Obama administration failed to live up to its promise, it’s Honduras, where its response looked like it came out of a Reagan-era playbook, and it was one of the first global crises that Clinton faced as secretary of state.

For good measure, Sanders should also press Clinton on whether she supports the Obama administration’s willingness to abandon a flawed, though democratically elected, leader in Egypt, Mohammed Morsi, and his replacement with a military authoritarian, Abdel Fattah El-Sisi.

Drones and the global war on terror

You don’t hear as much about unmanned attacks in the second term of the Obama administration, in part because there’s a sense that the government has backed away from the most controversial tactics, including so-called ‘signature strikes’ and targeting US citizens abroad, that caused such an uproar in Obama’s first term.

Clinton wasn’t running the military or the CIA, which both played a role in the drone campaigns in Pakistan, Somalia, Yemen and elsewhere. But it’s staggering that none of the debate moderators have forced her to defend, in an open and public setting, the rationale for drone strikes, the legal basis for assassinating US citizens abroad or the continued global imprint of a ‘war on terror’ that’s just as active today as it was during George W. Bush’s presidency. Though Clinton didn’t take the lead on these issues, they are probably the most important issues that aren’t being debated in either party’s presidential contest.

Would Clinton, for example, take a more aggressive approach by ratcheting up the frequency and severity of drone attacks? Her own record suggests she would, which might engender more anger and disenchantment with the United States. Sanders, of all people, is well-placed to argue that drone strikes are self-defeating because they do nothing to win the hearts and minds of young people across the Muslim world. So far, though? Nothing.