As we celebrate the July 4 holiday, Byron York of the Washington Examiner is taking stock of the Democratic presidential candidates.

There have now been five national polls since the first Democratic presidential primary debate. Together, the surveys, conducted by ABC News/Washington Post, Quinnipiac, CNN, The Hill/Harris, and Politico/Morning Consult, show the debate has shaken up the race. The field has separated into three clearly definable tiers, all atop a large group at the bottom made up of candidates with virtually no support.

Within the first tier — Joe Biden, Bernie Sanders, Kamala Harris, and Elizabeth Warren — the leaders’ positions are rapidly shifting. Since the debate, only one of the four — Harris — is up, while Biden, Sanders, and Warren are down. …

… That’s the first tier. After that, there is a big drop-off to a three-candidate second tier. In it are Pete Buttigieg (down from 6.6% to 4.8%) in fifth place; Beto O’Rourke (down from 3.3% to 2.4%) in sixth place, and Cory Booker (up ever so slightly from 2.3% to 2.4%) in seventh.

After that is a third tier of candidates — Julián Castro, Amy Klobuchar, Tulsi Gabbard, and Andrew Yang — who can muster 1% in the polls, but not much more. Castro, widely seen as having had a good debate, is up a bit, but the entire third tier is far, far back.

And then there is the large bottom group of candidates who are nowhere. Michael Bennet, Kirsten Gillibrand, Jay Inslee, Bill de Blasio, John Delaney, Steve Bullock, Tim Ryan, John Hickenlooper, and Marianne Williamson — they’re all at 0.4% or less. They were at the bottom before the debate and they’re at the bottom now.