The chaos that broke out at the presidential forum at Netroots Nation over the weekend in Arizona courtesy of the Black Lives Matter movement has sparked a debate about just how united the longtime Democratic coalition -- a pillar of which is almost-uniform support from black voters --really is heading into the 2016 election.

The shock and umbrage that protest generated has been pretty well covered -- as has Martin O'Malley's apology. But, there's something bigger here than a momentary spectacle. Can any Democrat win the presidential nomination, much less the general election without those protesters and people outside the hall who have been essential to President Obama's victories? And if not, what will candidates have to do, say, support and ultimately propose to get those voters to show up to the polls?

Netroots Nation is an interesting window into the Democratic coalition; the annual gathering tends to attract political nerds, staffers and political obsessives. It also tends be run by and supported mostly by whites. (Yes, we know that voting rights was on the agenda this year and that there was at least one session featuring black female bloggers, political commentators and the like. But, still.)

This year, the activists who seized control of the presidential candidate forum didn't think the talk about expanding economic opportunity and creating citizen panels to review police complaints was enough. Or even close. There may be corners of the Democratic and Republican electorate who insist that the worst of black America's current problems stem from the prevalence of inter-group violence, joblessness and the shape of many black families. But, for these protesters and people who support them, the reality that by June nearly 400 unarmed people had been killed by police this year, and that a staggering and disproportionate share of them were black, is not a concern. It is the concern.

Their logic boils down to this: Black life in America and the pivotal conversations between families, between friends, between parents and kids has always included some element of physical danger. Today, for reasonable and relatively informed black people, the discussion about that danger has to include what can happen when in proximity to violent criminals, armed and frightened private citizens and police. One of those groups enjoys state sanction, making them the most threatening of all. Unlike those other groups, even when there are legitimate questions about police wrongdoing, excessive use of force or unlawful shootings, the odds of indictment and conviction remain shockingly low, as The Washington Post reported in April.

And, of course, if the way that police sometimes do their work has enhanced the odds that you may wind up dead, maimed or in jail, paying attention to police makes a certain amount of sense. Reasonable people don't have to agree with that read on America or what imperils black life in this country. But that's where the activists who stormed into Netroots are at. And there's evidence that others are there with them.

Now, in complete fairness to O'Malley, Bernie Sanders and all the politicians who weren't there, the spectacle at Netroots this weekend could also certainly be described as just that -- an obvious ploy for publicity. The Black Lives Matter movement has, so far, made clear its ability to galvanize public interest, to draw press attention and to disrupt events as well as the flow of traffic in major American cities. And in the time since that Netroots showdown this weekend the movement and its supporters flexed some serious satirical muscle in Sanders' direction in the form of the hashtag #BernieSoBlack. (Prepare to laugh. Prepare to gasp. Prepare to understand that, at least on line, these folks are a force with which 2016 candidates must reckon.)

But what else has Black Lives Matter got? And to what extent is the Black Lives Matter movement prepared to work in or with the existing political system to transform their goals into policy?On Saturday night, at a film festival in Washington, D.C,  where organizers screened, "Vanguard of the Revolution," a new documentary about the rise and fall of the Black Panther Party, there were plenty of sobering reminders that the answers to those questions will matter. A lot.

Perhaps the most pointed came from former Black Panther Eddie Conway. Conway spent 44 years in a Maryland prison after a jury convicted him in the murder of a police officer. Conway has long claimed that he is innocent. Others have referred to him as a political prisoner. And in March 2014, Maryland prosecutors struck a deal with Conway.  Conway was released. His conviction stands.

When an inevitable question about the Black Lives Matter movement came from the audience at that film screening, Conway offered this: "At some point, these young people, the Black Lives Matter movement, will have to something more than lay down in the street. Spectacle, believe me, is only a start."