Retired Gen. John Allen delivered one of the most stirring, impactful speeches of the Democratic National Convention on Thursday night. It was a full-scale indictment of Donald Trump's foreign policy from the man who led the fight against the Islamic State.

But some Democratic delegates didn't want to hear it. They chanted "no more war" at the general as he made his case for Hillary Clinton and against Trump.

Retired Gen. John Allen's speech at the Democratic convention called for Hillary Clinton to be the next commander in chief. The crowd replied with loud chants. (The Washington Post)

To be sure, this was a relatively small contingent, and it was easily eclipsed by supportive chants of "USA! USA!" for Allen. But it was the second time in two nights this scene had played out. There was even more discord when former Obama CIA director and defense secretary Leon Panetta took the stage on Wednesday. Protesters chanted similarly at Panetta and held up handmade signs saying "no more drones."

But just how many Democrats agree with these sentiments?

This is, indeed, a divide that has existed in the party for years and was bound to be borne out at some point at this convention, given the party is nominating Clinton. She is known as a relatively hawkish Democrat, and she voted for the Iraq war. Some anti-war Democrats will never quite forgive her for that.

But this week's protesting wasn't so much about Clinton; it was about the Obama administration she served in. Much of it seemed to be in opposition to Obama's drone policies. And on that, we have polling.

A Pew poll last year showed a majority of Democrats — 52 percent — approved of U.S. drone strikes to target extremists. But 39 percent disapproved — higher than both Republicans and independents. In fact, three-fourths of Republicans supported them.

Among Democrats, that 39 percent disapproval was up significantly from two years prior, when 26 percent of Democrats disapproved.

In addition, while Democrats supported the use of drone strikes, a majority (55 percent) were also "very concerned" that they endangered civilian lives. Democrats were similarly more likely to worry about them leading to retaliation and damage America's reputation.

Republicans weren't nearly as concerned.

And when you drill down and only look at liberal Democrats, they're basically split in half on the overall question of drone strikes. From Pew:

There is a divide within the Democratic Party on the U.S. use of drones: Conservative and moderate Democrats approve of the drone attacks by a 56% to 36% margin. By contrast, liberal Democrats are about evenly divided (48% approve, 45% disapprove).

Of course, this isn't all about drones. Some of this is just the party's long-running anti-war contingent that has always been there in one form or another. It's hard to pin down how big this is in polling, but a CNN poll last year showed 6 in 10 Democrats did not believe the United States should lead the fight against ISIS.

But drones in particular epitomize this divide in today's Democratic Party, and they promise to be a continued source of tension between anti-war Democrats and Clinton if she becomes president.

Again, these have not been large protests — particularly Thursday's. It was perhaps to be expected at a Democratic National Convention at which Bernie Sanders delegates made up such a large contingent. Sanders re-litigated the case against Clinton's Iraq vote numerous times on the campaign trail for a reason.

But this was also a retired general on stage, drawing protesters. And it's clear that a Democratic Party that was divided between Clinton and Sanders is also somewhat divided on drones.

What happened on the fourth day at the Democratic National Convention

PHILADELPHIA, PA - JULY 28: Democratic Presidential Candidate Hillary Clinton celebrates with Democratic Vice Presidential Candidate Tim Kaine after accepting the nomination on the final day of the Democratic National Convention in Philadelphia on Thursday, July 28, 2016. (Michael Robinson Chavez/The Washington Post)