Bernie Sanders has a number of large disadvantages in his primary challenge against Hillary Clinton, from his long history outside the party to his near-total lack of elite support. But simply who he is — a straight, old, non-practicing Jewish man, with a laser-like focus on public policy — is proving to be perhaps Sanders' greatest handicap.

In short, black Americans — the Democratic Party's center of gravity — just aren't feeling the Bern.

This was clear in the South Carolina primary, where Clinton won by a crushing 74-26. According to exit polls, she did this mostly by running up a jaw-dropping 86 percent among black voters, greater than Obama's performance in 2008. (She won white voters too, but only by single digits.) If Sanders is to seriously contest the rest of the primary, he must connect with the black community.

Reporting from the campaign trail demonstrates how Clinton pulled off this victory. She and her surrogates are meeting tons and tons of black folks, speaking respectfully with them, and promising to address their priorities. Most of all, she is wrapping herself in the legacy of President Obama, promising to protect and defend his accomplishments.

It goes without saying that Obama, for extremely obvious and understandable reasons, is hugely popular in the black community. Sanders is running to Obama's left; his entire candidacy is premised on the Obama presidency being something of a failure. That's a tough sell for black audiences.

It's harder for someone like Sanders. As Joshua Cohen writes in a brilliant article about Sanders' political presentation, he has an instinctive aversion to talking about himself or representative people to illustrate policy. This is the bread and butter of modern political rhetoric, but Sanders prefers laundry lists of statistics and history. For most politicos, this would be the kiss of death, but he gets away with it because of his enormous credibility and rumpled charm.

It patently isn't working with black voters, however, and I'd guess cultural barriers are at least partly to blame. Sanders just isn't coming from a place of deep familiarity with black culture — and isn't religious either, yet another hurdle to connection.

However, as with the extensive labor support for the free-trading union-busting neoliberal, there is a bitter irony in Clinton's victory resting on black votes. In ages past she was a hardhearted tough-on-crime politician who played a nontrivial role in building the system that has locked up incomprehensible numbers of (mostly poor) black people. As a Black Lives Matter protester pointed out the other day, she used to indulge racist fearmongering myths about criminal "superpredators." Her husband's welfare reform bill increased the incidence of extreme poverty (heavily black and brown, it goes without saying) by 150 percent; she sold and defended the policy by invoking more right-wing slogans about government dependency. And despite her embrace of Obama today, her 2008 campaign against him was marred by obvious race-baiting.

Clinton has since disavowed those days; both she and Sanders now routinely note the need for racial justice issues such as police reform. But Sanders' economic agenda is several orders of magnitude more aggressive than Clinton's, and hence would help blacks the most, clustered as they are towards the bottom of the economic ladder. As Glen Ford argues, black Americans are on most measures the most left-wing demographic in the nation, yet are voting for the more conservative candidate. It ought to be possible to sell them on leftist policy.

After trying hard for quite some time, the Sanders campaign largely gave up on South Carolina last week, figuring their time was better spent elsewhere where they might have a better chance of winning. And while they could potentially make up several 20-point losses in the South, they couldn't get this trounced there and still have a shot at victory. He's simply going to have to give it a better shot.

Nevertheless, this campaign is far from over. South Carolina is only one state with its own idiosyncrasies, where Republicans have been utterly dominant for generations. As such, there is very little progressive infrastructure in place. Most critically, young voters barely turned out — 17-29 voters were a mere 15 percent of the electorate.

Sanders is an old man, but he's a better campaigner than he lets on, and has shown an impressive ability to adapt his message and incorporate new themes. He may yet surprise us again.