Hillary Clinton celebrates her South Carolina primary victory on Feb. 27. (Randall HIll/Reuters)
Opinion writer

There is no way around it. Hillary Clinton’s win in South Carolina’s Democratic primary was epic. We all knew Clinton wanted to run the table on Sen. Bernie Sanders (I). But her performance last Saturday essentially snatched the table from him and cast a pall over the rest of his candidacy.

Clinton trounced Sanders by 47.5 percentage points, winning 73.5 percent of the vote. Clinton’s support among African American voters – a whopping 86 percent — was even more stunning. Her total is eight percentage points better than President Obama’s won in 2008. Her overt appeals to Black voters proved wise. While they made up 55 percent of the vote in 2008, they were 61 percent of the Palmetto State turnout this go ‘round.

And as amazing as all those numbers are, they obscure a palpable lack of enthusiasm among Democrats. For all of Sanders’s talk of leading a political revolution among the Democratic base, the actual revolution is happening in the GOP. Look at these numbers.

The Democratic primary in South Carolina  last Saturday saw 162,701 fewer votes than in 2008. Meanwhile, the GOP contest in the Palmetto State a week earlier saw 306,721 MORE votes than in 2008. On top of that, Republicans cast 368,391 more votes than Democrats this S.C. primary season. During the 2008 S.C. primary, 101,031 more votes were cast by Democrats than Republicans.

Republican Donald Trump with family after winning the South Carolina primary on Feb. 20. (Jabin Botsford/The Washington Post)

If the party of Obama wants a third term in the White House progressive voters absolutely must turn out. Folks are kidding themselves if they think Trump’s steady march to the Republican nomination will be tripped up by his penchant for misogyny, xenophobia and racism. That’s what made him. And they would be foolish to think that he could not win the White House. He most definitely could — if Democrats stay home.

A key thing to remember is this: A Democrat will not need to win a majority of the white vote to win the White House.

President Lyndon Johnson’s 1964 election was the last time a Democrat won a majority of the white vote (58 percent). According to author Steve Phillips, the average is 39.91 percent of that vote for a Democratic presidential candidate. The author of “Brown is the new White: How the demographic revolution has created a new American majority” reminds in his important new book that Obama won reelection in 2012 with 39 percent of the white vote. Now, here’s the kicker. Phillips writes that the president “won reelection with 5 million fewer White votes than he received in his initial election in 2008.”

Obama was successful because of an avalanche of support from people of color. But his successor will be a Republican if they sit this election out. When that happened in 2010 — 26 million fewer Democrats voted than in 2008, the House flipped back to GOP-control. When that happened in 2014 — 14 million fewer Democrats went to the polls, Republicans took the leadership of the Senate.

Yes, those are mid-term election years, notoriously bad for Democratic turnout. Presidential election years are always better. But the primary contests so far show a party base that isn’t nearly as motivated as it was during the historic election of 2008.

Clinton and Sanders are running on messages that resonate with the Democratic Party base. Clinton is doing a much better job of making her campaign resonate in the ears of African Americans, the party’s most loyal constituency. But we’re seeing the first effects of an Obama-less ballot. That it would lead to lower turnout is not a surprise. That it would coincide with the rise of an enraged Republican electorate using a foul-mouthed bully as its avatar of raw anger is a surprise.

If the Republican presidential nominee, especially if that person is Trump, is to win, Democrats have to stay home. And if the vote totals in South Carolina and elsewhere are any indicator they already are.

Follow Jonathan on Twitter: @Capehartj