At the Democratic presidential debate this week, domestic policy got a lot of coverage. But foreign policy got comparatively little — and what the candidates did discuss was largely anodyne. This is a serious problem for Democrats, because while the party enjoys relative unanimity around domestic questions, there are sharp disagreements on national security ones. The candidates — particularly the left-wing challengers — owe it to the party to hash them out so voters can see the difference.

The major axis of contention, more or less, is about foreign intervention. One faction wants less of it, while another wants more. Hillary Clinton is very much in the latter camp — in contrast to much of the Democratic Party.

So when Anderson Cooper lined up an easy question for the other candidates to attack Clinton over excessive hawkishness, it was unfortunate that they punted. Everyone from Jim Webb to Bernie Sanders bent over backwards to emphasize how they were not against all wars, but only obvious disasters like the Iraq invasion.

Just as in the 2008 debates, the war in Afghanistan served as the go-to example of a good war that the left-leaning candidate could use to demonstrate his foreign policy bona fides. "I am not a pacifist, Anderson," said Sanders. "I supported the war in Afghanistan."

As Matt Yglesias points out, Sanders is basically an Obama Democrat on foreign policy. That alone would be enough to draw attention to Clinton's hawkishness. As secretary of state, she was on the belligerent edge of the Obama administration, pushing hard for the action in Libya and for more intervention in Syria.

And still, even the "Obama doctrine" itself could stand a serious overhaul. Take the signature Obama foreign policy tool: drone assassination. A huge new investigation from The Intercept, based on leaked documents, raises serious questions about the efficacy of this policy, particularly regarding civilian casualties and the accuracy of the targeting systems. There is a good chance any strategic benefit of the drone war will be undone by the chaos it has unleashed, not to mention the people driven to anti-American hatred by constantly circling death robots.

Or take the supposed Good War in Afghanistan. The whole U.S. effort in that country has been falling apart for years. On Thursday President Obama announced that he would be slowing the pace of the U.S. withdrawal from Afghanistan, after the Taliban made alarming advances in the north. U.S. troops will now remain until at least 2017.

Earlier this month, a U.S. airstrike hit a Doctors Without Borders hospital, under circumstances that remain murky. It appears American forces did know that the location was a hospital, but even if they didn't, it was still a devastating blow to the U.S.'s credibility.

It's increasingly obvious that Obama's vaunted "surge" in Afghanistan has been a complete failure. The country is no more stable now than it was in 2009. The ungodly sums spent on the occupation have totally warped the Afghan economy, which is already undergoing tremendous disruption as the U.S. prepares to depart. The government is weak, corrupt, brutal, and incompetent, and the Taliban are just waiting for the day the U.S. leaves to try and take over the country again. There's a good chance they'll peel off at least some of it.

But if 14 years wasn't enough time to train the Afghan army to defeat the Taliban, how long will it take? Is it even possible? Or is the U.S.'s outsized presence interfering with the process of state development?

It's almost exactly the same story as in Iraq, except that Afghanistan is a country dramatically harder to occupy. It has been the graveyard of empires going back to Alexander the Great. And so the U.S. is confronted with another politically tough choice: continue to fling good money and people after bad in its longest war in history, or admit humiliating defeat and crawl back home. I'd only bet on one thing for sure: If the occupation continues, things will be no better in 2026 than they are today.

Hillary Clinton's record suggests that, as president, she would continue or even escalate the Afghanistan occupation and the drone war, and continue arming whoever the U.S. is backing in Syria this week. She has few firm convictions, but foreign policy aggressiveness is one of them. Sanders and others at least ought to make her defend the U.S.'s disastrous record of recent overseas intervention.