Just a week ago, Bernie Sanders was surging in Texas, with one poll showing him winning by 15 points. His campaign proudly boasted that he would win the state where he invested in new campaign offices and held high-profile rallies. Yet on Super Tuesday, Joe Biden managed to capture the state, in large part because Sanders's solid support among Latino voters was offset by Biden's overwhelming support among black voters.

Some 3 in 5 black Texans voted for Biden, according to exit polls. In contrast, only 2 in 5 Latinos voted for Sanders. But seeing as black voters comprise a fifth of the Texas electorate while Latinos constitute a third, those figures ended up roughly equal.

However, Biden crushed Sanders among older voters, who made up nearly two-thirds of the overall electorate. Sanders dominated the youth vote, but he was unable to turn out enough of it.

Sanders's intense strength with younger voters, who comprise a smaller portion of the electorate than older voters, and moderate strength with Latinos, who comprise a larger portion than black voters, ultimately wasn't enough to offset Biden's bulwarks. Texas is ultimately a single state, but it's still a large one, and a victory there had to be part of any realistic path to the Democratic nomination.