Donald Trump speaks to supporters at a campaign rally at Oral Roberts University in Tulsa on Jan. 20. (Nick Oxford/Reuters)

What you’ve heard is true: There is indeed an underdog presidential candidate stoking a political revolution, luring the disaffected, disenfranchised, disengaged and demoralized off the sidelines and into voting booths.

Only a year ago, few took this candidate seriously. People laughed at his crazy hair, his New Yawk accent and sometimes his wardrobe choices. His populist, pie-in-the-sky policy proposals seemed unlikely to get him very far in 2016, when big-money super PACs ruled.

Pundits also questioned whether he could win the nomination of a party he had only recently affiliated with, especially since that would require defeating a well-connected establishment favorite, as well as some younger, fresher faces.

But he ignored the doubters and haters. And eventually he helped his newly adopted party score its highest voter turnout numbers on record.

I’m referring of course to Donald Trump.

What, you thought I meant Bernie Sanders?

That’s understandable.

Whenever Sanders has been asked about his “electability” in the general election, or how he could possibly get any of his lofty lefty ideas through an intransigent Republican-controlled Congress, he has crowed about the “political revolution” he will lead. Said revolution would be effected by mobilizing “millions and millions” of long-demobilized voters, who would finally make their democratic (and Democratic) wishes known.

“I believe that our campaign up to now has shown that we can create an enormous amount of enthusiasm from working people, from young people, who will get involved in the political process and which will drive us to a very large voter turnout,” Sanders said at the MSNBC Democratic debate this month.

Not only would the Sanders-generated turnout upturn score Democrats the White House, he argued, but also the Senate, “governors’ chairs up and down the line” and miscellaneous offices “across the board.” Political revolution: unlocked! Soon, anyway.

Unfortunately for Sanders, this revolution, at least as measured by turnout numbers, is flailing.

Sanders is indeed capturing healthy majorities of young voters and first-time primary and caucus participants, according to entrance and exit polls. But so far there haven’t been nearly enough such voters to award him a majority of delegates, let alone the kind of super-elevated turnout that would propel him to victory — along with like-minded confederates “up and down the line” — in November.

In fact, raw turnout numbers — that is, the number of people who voted — in all three Democratic contests thus far have fallen well below their record 2008 levels, according to data from University of Florida political scientist Michael P. McDonald.

Likewise, entrance and exit poll data so far indicate that first-time primary and caucus-goers have represented a smaller share of Democratic voters this primary season than in the past. For example, newbies accounted for 42 percent of Iowa’s Democratic caucus participants this year, versus 57 percent in 2008.

Historically, turnout has dropped off after early contests, too, which also bodes ill for Sanders’s promised revolution.

Meanwhile, on the other side of the ideological divide, a revolution does seem to be brewing: While turnout has disappointed in Democratic races, in each of the Republicans’ three contests thus far, it reached record highs.

Trump — an innovative politician if ever there were one — surely deserves much of the credit for these blockbuster numbers, just as he’s helped deliver blockbuster viewership for the primary debates.

His outrageousness, race-baiting, impossible promises and perfectly tuned ear for what constituents want to hear has helped bring disaffected Americans off the sidelines far more effectively than Sanders has. In Iowa, 46 percent of Republican caucus participants were first-timers this year, compared with 38 percent in 2012.

Does this mean that Trump will help deliver victories “up and down the line,” or at least further down the ticket to his ideological allies, as Sanders predicted for a left-leaning turnout surge?

Unlikely.

Remember that Trump has the highest “unfavorable” ratings of anyone still in the race. In fact, he has higher unfavorable ratings than any nominated candidate from either major party during any election cycle going back to at least 1992.

While he may be helping stimulate higher Republican turnout, newly engaged voters are motivated to visit the polls at least as much to vote against him as they are to vote for him. More so, in fact. In states where we have entrance/exit poll data, the majority of first-time Republican primary voters (as well as the majority of experienced participants, for that matter) voted for someone other than Trump.

Trump may be leading his party to revolution, but first he has to win its civil war.