The second phase of the 2020 race starts tonight

That narrative will begin to change right around midnight Wednesday, when the qualifying window for the third presidential debate closes. At the moment, 10 candidates -- out of the 21 still running -- have met the qualifications (130,000 individual donors, four national or early-voting state polls at 2% support or more) to make the debate stage in Houston on September 12.

Barring some sort of unexpected poll release, which, well, isn't going to happen, the race will split in two starting tomorrow between, broadly speaking, the have-a-chances and the don't-have-a-chances.

Sen. Kirsten Gillibrand was the first to drop, announcing Wednesday night that she was ending her campaign.

The simple fact is that if you are running for president but can't make it onto a debate stage that 10 of your fellow candidates made, it's going to be very, very hard to justify staying in the race all that much longer. How do you go to donors and ask them to give -- or give more -- to a candidacy that is, by the Democratic National Committee's standards, not in the top 10 most viable? And if you can't raise money, how do you pay your staff and run a real campaign?

(Side note: This standard doesn't really apply to Tom Steyer, who has the personal wealth to continue to fund his campaign for as long as he chooses.)

Even if a decent chunk of the "don't-have-a-chances" stay in the race in the near term -- maybe hoping to qualify for the fourth debate in October -- the perception that the race has now fissured between people who can win and people who can't will be very, very hard to overcome.

The coverage of the race for at least the next three or so weeks will be driven entirely by the upcoming debate -- who has the most on the line, who might surprise, etc. If you aren't one of the 10 candidates set to be on the stage (with, again, the exception of Steyer) then you will be yelling into the abyss. The race will be moving on, likely without you.

The reality is that the die is getting cast. Time is running out.

The Point: The way in which the DNC structures its debate qualification criteria sets up a natural winnowing of this giant 2020 field come September. Candidates below the cutoff line for the September debate can complain all they want about that fact, but it won't change the reality.