For months Bernie Sanders has tried and failed – and sometimes not even tried – to distinguish himself from Hillary Clinton on foreign policy. On Saturday, he finally found his line in the sand.

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The key distinction is this: in Syria, Clinton favors a focus on toppling Bashar al-Assad while simultaneously combating Isis. Sanders says overthrowing Isis must come first, and he also criticized her plans to go after Assad, calling her a “fan of regime change”.

Previously, Sanders had struggled to draw a substantive contrast between Hillary and himself beyond her vote to go to war with Iraq years ago. The monotonous attack made it look like he had no real foreign policy platform to speak of; finally, he has one.

He didn’t back down from his attacks on her vote on Iraq at Saturday night’s debate, but rather drew out its meaning, using it as a lens for the differing ways he and she see foreign policy.

“I worry Secretary Clinton is too much into regime change and too aggressive without knowing what the consequences will be,” he said, his clearest contrast with Clinton to date. “Yeah, regime change is easy, getting rid of regime change is easy, but … what happens the day after?”

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According to Sanders, Clinton is an interventionist who would have Americans charging into entanglements overseas without enough consideration for what comes next. It’s that very approach, he says, that, when Clinton was Secretary of State, drew the country into a quagmire in Libya; and it’s the same approach, he contends, that currently has the US facing a similar situation in Syria.

“The United States is not the policeman of the world,” Sanders said to applause –adding that the US cannot fight Assad and Isis at the same time. “The first task is to bring countries together to destroy Isis.”

Clinton painted Sanders as presenting a false choice, suggesting the clear dichotomy he described was born of foreign policy naivety. “When we look at these complex questions, I wish it could be either-or,” she said. “If the United States does not lead, there’s not another leader, there’s a vacuum.”

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That last line drew considerable applause – and recall that Saturday was the Democratic debate, with a less hawkish audience. If it plays well here, that line will play better later in a general election. That calculation may well be at the heart of Clinton’s strategy: she wants to make the case that she’s tough on foreign policy before the general election, and doesn’t mind coming off a little hawkish during the primary to get there.

Rhetorical devices aside, her foreign policy positions aren’t so different from the more centrist Republican candidates – leaving aside those who have threatened to raze entire countries with nuclear weapons. As The New Republic’s Suzy Khimm observed, Republicans in last week’s Republican debate “failed to articulate a vision for change in the fight against Isis that was fundamentally different than what Clinton is calling for”.

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Any noises that Republicans have made about no-fly-zones in Syria or the arming of Kurdish fighters – while they’re to the right of the Obama administration’s current positions – fall nicely in line with Clinton’s.

Finally, though, Democratic voters have a candidate clearly to Republicans’ left on these questions: Bernie Sanders. In one way, Sanders had his strongest debate yet by managing to distinguish himself on an issue important to his progressive base; it’s just absurd that it’s taken him this long to do so.

Until this fall, Sanders didn’t even have a foreign policy on his campaign website. And, after he came under scrutiny for the matter, he resorted to blasting out statements about Clinton’s vote to go to war in Iraq with zero other policy details. At the last debate – the day after the November Paris terror attacks – he missed another opportunity to distinguish himself on straight foreign policy and highlighted instead the global security risks inherent in not taking action on climate change (an issue which, along with immigration and women’s rights, was scarcely mentioned in tonight’s debate).

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His climate change comments, of course, were mocked by the right, and while his argument about climate change is valid, it was a missed opportunity to best Clinton during what is considered her worst debate performance to date.

After Saturday’s debate, though, Republican candidates didn’t deign to waste any breath on Sanders, who’s increasingly seen as not a credible threat to Clinton and, by extension, conservatives. But Jeb Bush did go after Clinton for saying that the US is in a good position to tackle Isis (not that anyone onstage at the Democratic debate was interested in talking about Bush).

In Clinton’s opening statement, she explicitly sought to contrast herself and other Democrats on stage with the Republican party, pointing to the general election. Sanders, this time, denied her the opportunity.

But that the Saturday before Christmas was the night Sanders chose to go on the offensive over foreign policy wasn’t a surprise; it just wasn’t the best strategy, as it’s largely expected to be the least-watched debate of them all.

So now that Sanders distinguished himself on foreign policy, the question remains if anyone will care.