Police and protesters speak, separated by a barricade, outside the Fourth Precinct police station in Minneapolis on Nov. 20. (Stephen Maturen/Getty Images)

First there was that incident at the Trump rally in Alabama. You know, the one where a protester with, shall we say, some ideas that are not terribly compatible with those of Trump or many of his supporters, showed up. He wound up on the ground, taking a beating and throwing some punches of his own before security booted him from the gathering.

And then this week, much of the country learned of news that what has seriously been described as masked men shot five people protesting what they believe to be a questionable police shooting near a Minneapolis police station late Monday.

Details of the first event are, despite what conservative media outlets have all but insisted, pretty clear. They were, after all, caught on tape. The particulars surrounding the second event — the shootings in Minneapolis — are developing. Three people have been brought into custody, while another suspect was released.

But there are some early hints of a possible theme here that cannot ignored. In both cases, protesters who identify themselves as connected to or concerned with the goals of the still relatively young Black Lives Matter movement became the targets of what appear to be politically motivated violence. Yes, politically motivated violence directed at one's perceived political opposition, other citizens.

[Conservative media offer a very different take on what Trump supporters did to that Black Lives Matter activist]

Violence, it seems, has reemerged as a kind of political commentary or expression, right here in the United States. Americans, or at least people living in the United States, have twice in the last week used violence in an attempt to silence or intimidate other Americans engaged in political protest.

Violence has always been there, sometimes in the shadows or the handiwork of hooded nighttime brigades who reinforced the goals of  keeping people away from the ballot box or, in some places, afraid to vote their conscience, publicly express concern or to formally protest some set of conditions. There have been, in recent years, protests that morphed into riots, but even here the damage has generally been done to property, not other private citizens expressing their political ideas.

And, of course, we are aware that there are Americans who have bombed, shot or plotted to somehow injure large numbers of private citizens. But again, those attacks have been generally aimed at America the country, the concept — not the politics of individual citizens or the organized groups they form.

What's remarkable about the events that America has witnessed in the last few days is the open and unabashed turn toward violence between potential voters, the effort of one set of political actors to crush or silence another by force.

There are many ways to explain this turn of events. One possibility that has to be considered is that race and racial frustration prompted the attackers — all of them white — to act in these cases.

We know that Americans across the country are increasingly convinced that the country has a significant racial problem. A new CNN-Kaiser Family Foundation poll released Tuesday shows that. The researchers behind it didn't gather data on what's making so many Americans feel this way, but dig just a bit beneath of what they did collect, and you'll see major differences in the way that white and other Americans respond to this question. While well more than 60 percent of black and Latino Americans described racism as a big problem, just 43 percent of white Americans did the same when contacted by CNN-Kaiser pollsters this year.

That kind of gap in the way that people view the country and its major problems is not just noteworthy in a statistical sense. It's a gap that likely drives large differences in the kinds of policy responses that different groups of Americans believe are needed — or that they will support politically. That difference of opinion — not the presence of President Obama or his alleged failure to erase the country's long-term racial challenges in seven years, not news coverage of that gap —is the most likely font of the strife that this week has become physical.

The only other feasible explanation is something that Trump supporters and those who are fundamentally opposed to or repulsed by the Black Lives Matter movement and its politics will appreciate even less. There is some public figure who has made a recent rise to national political prominence whose ideas have begun to incite violence. Sadly, this too is a very real possibility.