Until recently, Bernie Sanders has been as timid on foreign policy as he has been bold on domestic issues. On the domestic front, his strong stand on income inequality has helped shift the Democratic Party to the left, with frontrunner Hillary Clinton often rushing in to adopt Sanders’s positions. But on foreign issues, with the singular exception of trade policy (which is of course inextricable from domestic economics), Sanders has taken a much more gingerly approach. Until late September, Sanders didn’t even have a foreign policy page on his website and he rarely talked about international affairs except in the vaguest terms. 

But going into Tuesday's Democratic debate, it looks like Sanders is about to sharpen his foreign policy profile and highlight his differences with Clinton. In a press release on Sunday titled “Sanders’ Foreign Policy Experience,” the Vermont senator emphasized his 2002 vote against the Iraq war—an implicit contrast with then-Senator Clinton’s support of it. Will Sanders take the opportunity on Tuesday night to pounce on this difference and highlight an alternative foreign policy to Clinton’s approach? He should, as a Democratic president's foreign policy just might be more important in 2017 than his or her domestic policy will be.

In underscoring his anti-war credentials lately, Sanders is moving beyond the caution that has hitherto characterized his approach to foreign policy in the Democratic presidential primary. The foreign policy positions outlined on his website tack centrist, with a strong emphasis on fighting the war on terror, although including caveats about avoiding the unilateralism of the Bush administration. While more vocal than most Democrats in criticizing the military-industrial complex, there is little in Sanders policy positions to distinguish him from President Barack Obama. As Norman Solomon, executive director of the Institute for Public Accuracy, noted on Al Jazeera America, “While Sanders is a tiger on economic issues, he’s a restrained cat on foreign policy, hardly laying a claw on elites for their huge Pentagon budgets and interventions overseas.”

Sanders’s previous eggshell approach to foreign policy meant refraining from making the obvious line of attack on Clinton. In the 2008 Democratic primary, Obama effectively used the Iraq war as a wedge issue to win over the Democratic base. Sanders, until now, hasn’t followed the Obama playbook. Sanders caution is notable because foreign policy could be a fertile ground for him since Clinton remains more hawkish than most Democratic voters. (In calling for a no-fly zone and humanitarian corridors in Syria, Clinton has also staked out a more interventionist position than either the Obama administration or Sanders.)

Foreign policy should be central to the debate because it's one of the few areas where political differences between the candidates are crucial. American presidents have wide leeway in making foreign policy, but are much more restricted on domestic issues, especially if Congress is controlled by the opposing party. A President Sanders or President Clinton are likely to face an obstructionist Congress. So it is strange that so much attention is being given to the domestic differences between Sanders and Clinton, while foreign policy gets downplayed. 

Foreign policy presents both a threat and promise to Sanders. On the one hand, Clinton can play some strong cards. As the former secretary of state, she has a much more impressive record of hands-on engagement with foreign policy than Sanders can offer. By delving into foreign policy, Sanders could open the door to accusations that he’s a novice. On the other hand, by making Clinton’s relative hawkishness an issue, Sanders could reactivate the substantial number of Democratic voters who were leery of Clinton in 2008. 

Sanders has to figure out if he can make use of the narrow but real political distance between Clinton's hawkishess and Obama’s centrism. “As a candidate for president, Sanders has begun to make statements on foreign policy that Clinton never would,” Norman Solomon said. “Those statements amount to high jumps over a low bar of Clinton’s overt militarism. Yet, with the notable and laudable exception of Sanders’ opposition to NATO expansion (which Russia sees as a close-to-home military threat), there are few significant differences between his positions and Obama’s own foreign policy.”