Are the grassroots organizers for the two leading Democratic candidates different kinds of people? Photo: Ida Mae Astute/ABC/Getty Images

Back in August, BuzzFeed’s Evan McMorris-Santoro painted a picture of the famously unprofessional people-powered Bernie Sanders campaign with its vast crowds at un-slick monster rallies — but offered a contrasting image of an old-school professional campaign in the critical early states of Iowa and New Hampshire.

Twin operations — what one senior aide called “parallel campaigns” — are under construction. First, there are the traditional paid operations in Iowa and New Hampshire. And second, a digital operation designed to harness Sanders enthusiasm into a relatively low-cost, high visibility national volunteer grassroots army.

Now’s the moment for the blossoming of the early-state campaigns, and the New York Times’ Trip Gabriel and Amy Chozick offer a close look at what Team Sanders is doing in Iowa. Here’s a key data point:

The campaign has quietly assembled an extensive ground game here, with 100 paid staff members and with trained volunteer leaders for each of the state’s 1,681 caucus precincts.

The field team is meant to be the engine for a Sanders upset in the caucuses on February 1 — the vehicle to turn out the tens of thousands of grassroots supporters who show up for Mr. Sanders’s rallies, even if they no longer earn him headlines.

One hundred paid staffers is a lot for Iowa; 1,681 trained volunteers is a lot, too. But Team Sanders claims a qualitative as well as a quantitative advantage in Iowa:

Pete D’Alessandro, Mr. Sanders’s Iowa campaign coordinator, compared his field team to the Continental Army taking on the British Redcoats. “We don’t have a roomful of kids saying, ‘If I do this well maybe I’ll be working in the State Department next year,’” he said. “They’re not motivated by that.”

Aside from noting that d’Alessandro himself is a seasoned pro — he was Bill Bradley’s Iowa political director back in 2000 — the idea that Bernie’s people are driven by idealistic enthusiasm and Hillary’s by coldly calculated ambition is worth pondering for a moment. The former attribution is the sort of thing that was often said about Obama’s field operation in 2008 — until many of its veterans turned up in jobs ranging from the White House to the press and political-affairs arms of federal agencies, where they helped formulate and defend a lot of the policies and strategies now denounced by progressive activists as unprincipled, if not corporate-whorish.

The thing about enthusiasm is that the more convinced you become that you’re riding a rampant tiger, the more you are likely to consider the possibility of total victory, and the spoils that come with it. Certainly many young Sanders field staffers are perfectly willing to go back to such iffy endeavors as the struggle to climb onto the slippery pole of an academic career, or the fight for those rare entry-level gigs in journalism, or the perilous life of a freelance this or that. But the more a nice stable gig with actual benefits at the U.S. Department of Agriculture becomes realistic, the more ambition may sneak into the most selflessly patriotic mind. So as the fight for Iowa and New Hampshire grows intense, I suspect the Sanders and Clinton staffers will become mirror images of each other, even if they drink at different bars.

This does leave the rarely asked question of what motivates Martin O’Malley’s team. I’d say it would have to be a very, very long-range view.