On Monday, I wrote about a picture showing more than 19,000 people packed into a basketball arena in Portland, Ore., to hear Vermont Sen. Bernie Sanders speak. The picture above, from a Sanders rally in Los Angeles on Monday night, shows a reported 27,500 people gathered to "feel the Bern." (Worth noting: That crowd estimate comes from the Sanders campaign, so take it cum grano salis.)

That's a stunning number of people to hear ANY candidate at ANY time during ANY election cycle. Much less a major underdog for the Democratic nomination in the year before an election.

So, how does Sanders do it? This from WaPo's Ed O'Keefe and John Wagner:

About a week before each Sanders rally, the campaign sets up a Web page advertising the location and blasts out an e-mail to supporters in that geographic area, asking them to RSVP. The events are also promoted on Facebook. And from there, things tend to take on a life of their own.

That sort of organic passion and energy is the sort of thing that any politician -- especially one named Hillary Clinton -- would love to have at their back. (As O'Keefe and Wagner note, the largest crowd Clinton has had in this campaign is 5,500.) Sanders has it -- big time.

That doesn't mean he beats Clinton for the nomination. Or even comes close. But it does mean that something is going on out there. Sanders's populist, anti-Wall Street message is resonating. Crowds the size he gets don't lie. And they shouldn't be ignored.