Sen. Marco Rubio (R-Fla.) has never won a presidential primary. That didn't change on Saturday, when Rubio lost the South Carolina Republican primary, finishing behind angry rich guy Donald Trump for the third time this primary season.

Now Rubio has lost again. But his campaign was painting him as the "real" victor even before polls closed:

Just reported on @CNN Rubio HQ is feeling bullish, advisers believe he could be strong 3rd or 2nd. If that's case, expect a triumphant tone — Manu Raju (@mkraju) February 20, 2016

CNN chyron right now: "SOURCE: RUBIO CAMP SAYS THIRD PLACE WOULD BE A 'VICTORY'" — Colin Campbell (@BKcolin) February 20, 2016

Here's the truth: Although the primaries are far from over, Rubio faces an uphill battle to secure the nomination, and Saturday night's loss was his worst yet.

Here's why. As my colleague Janie Velencia explained on Friday, Republican primary voters don't directly elect their presidential nominee. (Neither do Democrats, but that's another story.) Instead, they elect delegates, who will pick the nominee at the Republican National Convention in July.

Iowa and New Hampshire award delegates proportionately based on the percentage of the vote each candidate receives. So despite losing those states, Rubio got some delegates: seven in Iowa and three in New Hampshire. (Donald Trump has 17 delegates; Sen. Ted Cruz has 11, just ahead of Rubio's 10.)

But South Carolina awards all of its delegates to the statewide winner and the winner of each congressional district. The statewide winner gets 29 delegates; the candidates who finish second and third statewide get nothing. Zero. Zilch. The winner of each congressional district gets three delegates. Second- and third-place finishers get nothing except a scolding by Gene Wilder:

If Rubio doesn't win in any of South Carolina's seven congressional districts -- and the early returns suggest Trump will win all of them -- he'll get zero delegates. Even if Rubio pulls out a win in a congressional district -- or two -- Trump will win the vast majority of the state's 50 delegates.

So what's Rubio hoping for? Former Florida Gov. Jeb Bush suspended his campaign Saturday night. But there's no evidence that enough of his voters will go to Rubio to allow Rubio to finish ahead of Cruz, let alone Trump.

Breitbart's Ben Shapiro has another theory about Rubio's plan:

Rubio plan:

(1) 3rd in IA;

(2) 5th in NH;

(3) 2nd in SC;

(4) 2nd in NV;

(5) 3rd in most of the South;

(6) ....

(7) GOP nominee! — Ben Shapiro (@benshapiro) February 19, 2016

Shapiro is referencing the Underpants Gnomes, characters on the television show "South Park" who had a bizarre and somewhat unrealistic business plan:

South Park

It's a joke, but Shapiro's right: If Rubio wants to be the Republican nominee, the senator really needs to figure out what his plan is. Because right now, Trump is winning.

At this stage, add Bush’s number to Rubio’s and they still don’t beat Trump. Which is why Rubio would need to find a way to get Kasich out. — Matt Viser (@mviser) February 21, 2016

Trump becomes the fourth Republican since 1980 to lose Iowa, then win both NH and SC. The others were Reagan '80, Bush '88 and McCain '08. — Steve Kornacki (@SteveKornacki) February 21, 2016

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