One week ago, I wrote that "Donald Trump could get an effectively insurmountable delegate lead in just 21 days."

After Super Tuesday, he appears on track to do just that, or something close to it.

Trump had an excellent night on Tuesday. He won seven of the 10 states that have been called so far. He'll likely emerge on Wednesday with a sizable delegate lead over Ted Cruz and an enormous one over Marco Rubio, due to delegate allocation rules in several large Southern states that disadvantage third-place finishers.

And, perhaps most importantly of all for Trump, it appears that his opposition will remain divided. Ted Cruz, Marco Rubio, and John Kasich all got pretexts they can use to justify remaining in the race — Cruz won Texas and Oklahoma and will be second place in delegates, Rubio finally won his first state with Minnesota, and Kasich seems to have effectively tied Trump in Vermont.

That's crucial because so many delegates are going to be allotted in the next two weeks. By the time the dust settles on March 15, 58 percent of delegates will be bound to one candidate or another. And if Trump has two more weeks of victories like he's gotten already, his delegate lead after the Ides of March could be all but impossible for any other candidate to surpass.

The theories about how Trump could be stopped have always entailed a big, fundamental change to the race — either a collapse of Trump's support or a consolidation of anti-Trump voters behind just one candidate.

But these two things keep not happening. They didn't happen on Super Tuesday. And if they don't happen in the next two weeks, Trump is on track to win.

Cruz, Rubio, and Kasich all got excuses to stay in the race

Trump's wins in most of the Super Tuesday states are obviously great for him. But perhaps even more important was what happened in the states he didn't win.

First, Ted Cruz's wins in Texas and Oklahoma mean he isn't being driven out of the race as many Rubio allies hoped. He'll stay in, and for good reason — once all the delegates are allotted, his big Texas win all but ensures he'll be second in delegates overall (far ahead of Rubio).

But Cruz's triumph is also great news for Trump — because the Texas senator doesn't seem to have a path forward. Yes, he's second in wins and delegates right now, but that's mainly a function of his home state and the calendar. Indeed, the South was supposed to be Cruz's strongest region, and yet Trump has won six of the eight Southern states that have voted so far. Many of the states Cruz will need to win in order to catch up to Trump are in the Northeast and West. But he's done poorly in those regions so far, and not enough Southern states are remaining to save him.

Second, Rubio had a disappointing night. Yes, he did finally win a state in Minnesota. But he had little else he could brag about. Delegate allocation rules favoring the top two finishers in the big Southern states where Rubio finished third — Texas, Alabama, and Tennessee — could put him well behind Cruz and hugely behind Trump in delegates.

So Rubio is weakened going into the contest that truly means life or death for his campaign — Florida, on March 15. It's no accident that Trump held his Super Tuesday victory press conference in Florida and mentioned his hopes to beat Rubio in the latter's home state several times. Trump is up 20 points in the RealClearPolitics polling average for Florida, and the state is winner take all, making it an enormously consequential delegate prize. If Cruz and Kasich stay in the race, as now appears likely, that could make it even easier for Trump to win the state with a mere plurality. And that would be the end of Marco Rubio.

Third, there's John Kasich, who appears to be doing Trump an enormous favor by remaining in the race. Kasich will pick up hardly any Super Tuesday delegates, but he seems to have effectively tied Trump in Vermont and tied Rubio for second in Massachusetts, which gives his campaign at least something to point to to justify staying in the race.

Yet Kasich, too, seems to have no path forward, since he performs so poorly outside deep blue states. So if he is in fact pulling more votes from Rubio than Trump, and he's still in the race on March 15, he makes it easier for Trump to win not only Florida but also Kasich's own state of Ohio (where Trump has also led the one recent poll) with just pluralities.

The race could still change! But if it doesn't, Trump wins.

The argument that Trump will lose has always been premised on the idea that the race will, at some point, fundamentally change.

And, in theory, that's always been perfectly plausible. If the race fundamentally changes from how it looks now, Trump could definitely lose!

But nothing in Super Tuesday's results implies that any fundamental change is around the corner. No, the Ku Klux Klan flap didn't cause Trump's support to collapse. No, the results didn't reveal any new nationwide rallying around Rubio as the leading anti-Trump contender. No, the outcomes won't drive Cruz, Rubio, or Kasich out of the race.

Instead, these results looked quite a lot like we've already seen — Trump winning many victories with percentages in the 30s and 40s, and his opposition divided and looking likely to remain so.

That can still change. But for the "Stop Trump" movement, time is of the essence. After March 15, 58 percent of delegates will already be allotted. The bigger the lead Trump amasses in this period when so many delegates are at stake, the more likely it will be prohibitively difficult for any one candidate to catch up to him.

Remember, Trump is certain to keep accumulating delegates after March 15. A third of the remaining delegates are in the Northeast — his home region, where he has run strongly and both Rubio and Cruz have run weakly so far, including the billionaire's home state of New York and nearby New Jersey. And many of these states award their delegates proportionally or by congressional district, all but ensuring Trump will pick up a good deal of them unless his support suddenly vanishes.

So last week GOP elites had 21 days to stop Trump. Now they have 14. And they didn't make much progress in the interim. We'll see if they can manage to do so in the little time they have left.

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