When Democratic presidential candidates have campaigned in Los Angeles, it has usually been around a private fundraising event featuring Barbra Streisand or Steven Spielberg or George Clooney – or some combination of the three.

What it has not been about – especially some 15 months before Election Day – is a long-shot, underdog candidate’s drawing a crowd of 27,500, which socialist Sen. Bernie Sanders of Vermont did, energizing enough people to more than fill the Los Angeles Memorial Sports Arena (right after he, in the preceding two days, attracted throngs of 28,000 and 15,000, respectively, in Portland and Seattle).

Let me assure you that candidate crowds are not, unlike sunsets and thunderstorms, natural occurrences. Large crowds are anything but spontaneous; they have to be organized. Traditionally, to “build a crowd” for a candidate’s appearance, there has been a basic political rule: If your candidate is speaking in a hall that holds 500 people, be certain that you will have a crowd of 750. To do so, that used to mean recruiting dozens of volunteers running phone banks to invite several times that many, often providing free transportation and free food, as well as entertainment. This meant spending a lot of hours and more than a few dollars.

Why all this effort? The size and response of the crowd can determine the candidate’s press coverage. The last opening sentence any campaign ever wants to hear is, “Speaking to a half-filled high-school auditorium…” An unexpectedly large, enthusiastic crowd – exactly like the ones Sanders alone, of all the 2016 candidates, is regularly pulling – all but guarantees positive media reports. In addition, big crowds, beyond arousing voters’ interest, can convince a skeptical press corps or political world that a previously discounted campaign needs to be taken seriously.

Of course, online communication streamlines contemporary voter contacts. A week before a Sanders rally, a Web page appears. Invitations are sent, and RSVPs are requested. But though methods and mechanics change and improve, politics is still fundamentally about the message and the messenger.

Bernie Sanders, his growing legion of supporters would concede, is no matinee idol and does not hide his 73 years. He doesn’t look to have wasted time on his personal appearance, and he definitely buys off the rack. He does not offer the optimism that characterized both John F. Kennedy and Ronald Reagan or the eloquence of an Adlai Stevenson.

No, what Sanders gives you is his unvarnished take on the truth. To the hedge fund royalty and the private-equity princes, he announces: “You can’t have it all. You cannot get huge tax breaks when millions of kids go to bed hungry. … You cannot hide your profits in the Cayman Islands and Bermuda. You will pay your fair share.” Audiences understand when Sanders declaims that uncontrolled campaign financing – with admitted individual contributions of $10 million to a candidate – because of the Supreme Court’s 2010 no-limits Citizens United decision has “totally corrupted” this nation founded on “government by the people.”

In the most recent campaign reports, Sanders and Republican neurosurgeon Ben Carson are the only two candidates who have raised more than 80 percent of their funds from contributions of $200 or less.

If citizens cheering in the Sanders crowds decide to contribute, say, $25 or $50 each, then you could have a new narrative for the 2016 presidential contest. This really could be David against all the Goliaths in both parties – the last, best chance to take back the American government from big money. This is why the big 2015 Sanders crowds could really count.

Editor’s note: To find out more about Mark Shields and read his past columns, visit the Creators Syndicate website at www.creators.com.