African-Americans are the bulwark of the Democratic Party. In many Southern states, blacks account for as much as half the Democratic vote. Without the black vote, Barack Obama would not have won two terms in the White House. It is no wonder then that Bernie Sanders and Hillary Clinton have been courting that constituency in every way possible in the last few days.
Mr. Sanders, the senator from the pale-faced state of Vermont, had a bit of catching up to do. Hillary and her husband can draw on decades of history in Arkansas and in the White House campaigning among black voters and working with black leaders. Mr. Sanders has spent more time dealing with the concerns of dairy farmers in the Green Mountains and country store owners along the Winooski River.
Not that Bernie lacks a history with the Civil Rights Movement. As a young 1960s activist, he took part in the 1963 March on Washington and helped integrate student housing at the University of Chicago. Those credentials, plus his consistent progressive record in politics, won him the endorsement of the African-American movie director and activist Spike Lee, who cut a radio ad on his behalf.
Clinton countered with her own Hollywood endorsement from Morgan Freeman -- "the voice of God" -- who has narrated two TV ads for the candidate. In one ad, Mr. Freeman says of Hillary, she has "always stood with us." By "us" he clearly means black Americans.
Of course, they have not always stood by her. In the 2008 South Carolina primary, black voters in large numbers abandoned the Clintons and gave their ballots and adoration to Mr. Obama. This provoked Bill Clinton to famously lose his cool and say some things about Mr. Obama that he quickly regretted. No permanent damage was done, however. When Democrats cast their votes in Saturday's South Carolina primary, Hillary is expected to easily beat Mr. Sanders, thanks to the renewed allegiance of black Democrats.
African-Americans may give her additional victories today, Super Tuesday. Six of the 11 states that are choosing both Democratic and Republican delegates are Southern states with large black populations. Still, Ms. Clinton does not have a lock on those votes the way Mr. Obama did. She's showing vulnerability in the same place she has proven weak with the broader Democratic electorate: young people.
Younger black voters are not nearly as enthralled by Hillary as their parents are. Like their white counterparts, many are attracted to Bernie's bold leftist politics. That is one reason the Mr. Sanders campaign is working for an upset victory in Virginia, which, added to probable wins in Massachusetts and Vermont, could deny Ms. Clinton a Super Tuesday sweep.
Whoever their nominee turns out to be, Democrats will face a serious challenge with their most loyal base of voters in the general election. Enthusiasm for Mr. Obama drove African-Americans to go to the polls in record numbers in both 2008 and 2012. A host of them stood in line for long hours in precincts where -- either by poor planning or insidious design -- election officials had provided inadequate resources to expedite voting. Defying the impediments, they were proud, resilient and determined to make history. Can either Mr. Sanders or Ms. Clinton come close to inspiring a similar devotion in black neighborhoods this time around?
Were the full power of the black vote ever mustered, there are several bright red Southern states that could turn blue. Republican dominance of the South would be shattered. That probably will not happen this year. However, in swing states like Ohio and Florida and Michigan, African-American votes may be the pivot on which rests victory or defeat for the Democratic candidate.
For Bernie and Hillary, these are indispensable voters. And if it means buying lunch for Al Sharpton, so be it.