Bernie Sanders fell so far behind Hillary Clinton Tuesday night that it's all but impossible for him to catch her, barring some sudden and seismic change in the race.

Last week, I wrote a post laying out what would have to happen for Bernie Sanders to pull off an improbable comeback victory.

And in Tuesday's elections, he didn't even come close to those targets.

The votes are still being counted in some states, and Sanders was leading Missouri at press time. But Democratic proportional delegate allocation rules mean that if a race in a state is close, the identity of the winner barely matters — both candidates will get a comparable amount of delegates.

The states that matter the most for the delegate count are, instead, the landslides. Before Tuesday, Clinton had already built up a lead of 215 pledged delegates over Sanders due mainly to her landslide victories across the South.

And the landslides tonight all went in Clinton's favor. At press time, she was:

Winning Florida by 31 points

Winning Ohio by 13 points

Winning North Carolina by 14 points

So since Illinois and Missouri are close races where the delegates will be split pretty much evenly, Clinton's pledged delegate lead will expand substantially as a result of these blowout wins — from 215 to around 315. And of course, that's not even to mention Clinton's enormous superdelegate lead.

Sanders would have to win practically every remaining state by gigantic margins to catch up in pledged delegates

Here's how rough the math is for Sanders going forward: To win a majority in pledged delegates, he needs to win 58 percent of those remaining.

That might not sound so bad. But because all the Democratic contests allot their delegates proportionally, it's actually punishingly difficult.

It means Sanders has to beat Clinton by around 58 percent to 42 percent pretty much constantly. And that's just incredibly implausible given what's happened so far, and especially given what's happened tonight.

Even unexpected wins for Sanders in big states like California, New York, Pennsylvania, and New Jersey — already unlikely — wouldn't be enough. Sanders has to win those states by enormous margins.

And there are still a great deal of delegates left in states and territories with large nonwhite populations — states with demographics similar to those that have favored Clinton so far. These include Maryland, Arizona, New Mexico, and even Puerto Rico (which Clinton won in a blowout in 2008).

Plus, any further Clinton victory just makes the targets Sanders has to hit even more absurd. At this point, the only thing Sanders can really hope for is that some scandal emerges that tanks Clinton's numbers everywhere. Other than that, she's well on track for an easy victory.