Sen. Bernie Sanders had a heck of a day Tuesday.

The presidential candidate scored an unexpected and significant victory in Michigan, adding real-world evidence to his campaign's claims that he can continue all the way to the Democratic National Convention. Sanders posted a two-point win, narrowly carrying the kind of state he has lacked -- a big one with a sizable black population. His opponent, Hillary Clinton, still beat him 2 to 1 among black voters. But Sanders earned a larger share of the black vote in Michigan than he has in any preceding state.

That's the good news for him. This post will admittedly not be about that. So, Sanders voters -- particularly those keyboard gangsters, frequent commenters and tweeters, and those convinced of a grand media conspiracy to end the Sanders campaign -- prepare. This piece is about another aspect of the Sanders campaign and some of you.

Something -- we cannot say what -- inside certain corners of the ostensibly progressive and overwhelmingly white ranks of Sanders voters is amiss. There is a pattern -- demonstrated time and time again -- by both Sanders and some Sanders supporters of racial cluelessness, an infantilizing and almost colonial kind of condescension about policy, and a tendency to react to anyone who points that out by, well, supplying even more evidence of racial tone-deafness, self-ordained intellectual superiority and sometimes completely open displays of various forms of outright bigotry.

That's right. We said it. In trying to make their case, Sanders, and far more often some subset of his supporters, behave in ways that are difficult to square with their claims to progressive politics and building a more inclusive and egalitarian society.

One final note before we get to a few examples of the behavior characterized above: The portion of Sanders supporters who read the paragraphs above and began to compose their tweets, emails and below-story comments, we are aware of that Intercept piece that argues that the "Berniebro" and his alleged public misbehavior is media-generated fiction.

But the emails, Twitter messages and comments I have received tell a different story. They use a variety of curse words and insults typically reserved for women. More than one has suggested that I deserve to become the victim of a sex crime. They critique the "objectivity" of what is clearly political analysis based on polling data and other facts; they insist that black voters are dumb or that I have a personal obligation to help black voters see the error of their Clinton-voting ways. It is vile. And it stands in sharp contrast to the claim that no portion of Sanders supporters are angry people who sometimes engage in or embrace bigotry.

We could print the emails. But those of you who sent them know who you are and the horrendous things said. We doubt that this would do much for your progressive street cred.

Now, for those promised details.

In late July, a stand-up comic in Berlin who uses the Twitter handle @joshwithpowers posted a message that contained a series of hashtags. If they have a theme, they appear to be puns using Sanders's first name.

Did you catch it? #MississippiBerning is not simply a clever play on words. This Twitter user's possible joke was arguably tasteless. "Mississippi Burning" is the name of a 1988 Oscar-nominated film that fictionalized real-life FBI efforts to solve and see prosecuted the 1964 killings of a trio of civil rights workers in Mississippi. The film also tried, in its own way, to make clear the organized domestic terrorism that any black person who attempted to vote or exercise other rights often faced. In short, for millions of black Americans, life in the South was only slightly different in 1964 than it was in 1864. This is not a time to celebrate. It was a movie about a set of practices, typically gruesome crimes and threats, often unaddressed by local law enforcement officials or even carried out by them.

But one can argue that comedy goes to uncomfortable and distasteful places sometimes -- and through that, it can constitute a valuable form of social and political commentary. The problem -- the real revelation here -- came in what happened next.

One person used the same hashtag the following day, then there were a few scattered mentions between August and February. Some of the people behind these messages appear to be Sanders supporters. Then, on Tuesday morning -- the day of the Mississippi primary -- a Twitter account dubbed GrassRootsForSanders (@GRForSanders) used the hashtag in a morning voting reminder for Mississippi residents. And it seems to have caught on with some Sanders supporters earnestly trying to mobilize Mississippi voters from there. We have had to include a screenshot because the Tweet and some others using the hashtag appear to have since been removed.

This thing may have started as a joke -- knowing or not -- about the sound of Sanders's name and assertions that Sanders's campaign messages are catching on -- spreading like wildfire. But for much of Tuesday, there was clearly some portion of Sanders's voter base that either saw no problem with the hashtag or convinced themselves that the brutality and violence that the term symbolizes as well as the real loss of three young progressive activists just didn't matter enough to skip the hashtag.

A predictable backlash began online. We'll direct you here if you would like to read a portion of the litany. But one tweet, sent by a user with a handle we cannot print, probably put it best.

“This #MississippiBerning hashtag is the worst idea ever," the tweet said. "It’s like everything wrong with his campaign distilled down to a fine white powder.”

As per usual, more than a few Sanders supporters tweeted claims that it was all a joke or that some portion of the Sanders electorate had been suckered by the cruel handiwork of a troll. That may be true. But the fact is that many, many people used it -- until the complaints began. And the larger problem is that this really wasn't the first display of offensively dismissive, superior, let-us-tell-you-black-voters-what-you-need-and-how-you-should-vote commentary from some subset of Sanders supporters.

When Sanders made an effort to boost his black-voter support in South Carolina, and then again on Super Tuesday, Clinton claimed victories with black voters just as big as before -- 9 to 1 in some Southern states. And instead of taking from that outcome that the Sanders campaign may have work to do, how many times and how many ways did the campaign and some Sanders supporters say or write some version of this? "Black voters, if they knew what was best for them, should be with Sanders. If they weren't so brainwashed by the Clinton mystique and awash in 1990s nostalgia, if they weren't so poorly informed by the corporate-controlled media, if they just knew how to think a little more deeply then, of course, they would be Sanders voters."

Honestly, is that what it means to be a progressive in 2016? Does no part of that make some portion of Sanders voters squirm?

The degree of arrogance and paternalism inherent in that thinking is pretty astounding. But there is also a cold, hard truth that Sanders and his supporters have to face: Without more black votes -- or results that look more like Michigan's than the states that came before it -- Sanders simply cannot win. Black voters make up a large and reliable share of the Democratic Party's voters. This behavior will sabotage his campaign.

No one is saying that the language or attitude described above rivals violent racism or even the kinds of religious immigration tests that have been proposed by presidential candidates in the other party. But we are saying this. Black voters are also just that: voters, with functioning minds and political priorities, not pets. Every candidate should be prepared to craft an appealing platform and then tailor not the content but the presentation of their policy ideas for different groups of voters. That's what it means to campaign, to compete for voters in a democracy.

To put this another way, perhaps the Sanders campaign could spend some time adjusting, for example, the way that its $15 minimum wage proposal is presented and explained to voters for whom $15 hour is nearly twice what they earn right now. It should not really be hard to imagine why getting $15 through a likely Republican-controlled Congress may not sound feasible to such a worker. A large share of these people are women of color, a group among which Sanders has, until Tuesday, done terribly. Perhaps he could augment his core message about out-of-control economic inequality with more information about the role that increased attention and enforcement of wage equity laws would play in a Sanders administration. Perhaps he should identify the types of concessions he would be willing to make on, say, tax policy, to turn a $15 minimum wage federal law. Pragmatism does not make a voter dumb. Thus far, Sanders's race and gender-neutral message about income inequality have not done the job. Remember, Clinton outdid even his improved performance with black voters in Michigan, by more than 2 to 1.

We also will not leave out, of course, the comments Sanders made during the Sunday debate indicating that to be poor is to be black and to be black is to have experienced life in a ghetto. Again, we really can't discount completely any claims that this was verbal slip from a nervous candidate in a high-pressure situation. Maybe that's exactly what it was. But Sanders said what he said.

We can -- and many political reporters rightfully did -- raise questions about Sanders's command of the facts about poverty in the United States and just why his ideas happen to comport with a range of inaccurate racial stereotypes. And we certainly will not pretend that anything about his day-after-the-debate explanation for that answer amounted to an improvement.

Instead of saying something to indicate that what he said may have been offensive or inaccurate and clarify a more accurate and salient point about the nation's poor, Sanders seemed to double down.

“What I meant to say is when you talk about ghetto -- traditionally what you are talking about is African American communities,” Sanders told reporters in Detroit the next day.

Voters of all races and ethnicities, genders and ages -- particularly anyone trying to assess Sanders and Clinton in the next few states where primary contests will be held -- are watching. They are listening. They too can see the online comments from whatever share of Sanders supporters who unleash real vitriol every day. The same certainly can be said for the #MississippiBerning hashtag and it's prolonged and earnest, if clueless and insensitive use.

This, folks, comes pretty close to Republican presidential candidates declaring theirs the party of diversity and inclusion while the GOP presidential front-runner has embraced exclusionary ideas over the course of the campaign. Just because Sanders and his supporters have declared themselves the most progressive, equality-loving, radical actors in the 2016 political game does not make it true for others.

Nor do those self-assigned labels suspend the ability of others to observe and vote accordingly.