(Brian Fung / The Washington Post)

Joe Biden has said a lot of strange things in his time. For the loose-lipped vice president, however, even this was a new one.

"Trust me," he told voters last month. "You don’t want a Death Eater like Malfoy as your congressman."

Biden's remarks came near the feverish end of a heated Democratic primary battle whose candidates included, among others, the son of an impoverished government bureaucrat, a professor of transfiguration and a groundskeeper who's half-giant by birth. The winner would go on to confront Slytherin incumbent Draco Malfoy in a race to represent the state of Columbia's 22nd district.

You may already be guessing that the primary was a fiction, perhaps J.K. Rowling's stab at a "West Wing"-themed reboot of the Harry Potter franchise. You're right, of course: The 22nd district of Columbia doesn't exist. Hermione Granger never wound up endorsing Neville Longbottom — and neither did Biden, for that matter.

But with the real midterms fast approaching, Democrats are eager to put more people in the field who've been trained in the latest campaigning techniques. That means spreading some of the technological lessons of the 2012 presidential election down to smaller state and local races. It means giving people who've never seen a line of HTML the power to write their own. And it means applying the pressure of an actual campaign to be sure those skills stick.

Hence the wargame for Columbia 22. Established by the New Organizing Institute — the left's think tank for campaign know-how — the annual exercise introduces dozens of recruits to what's now a standard feature of 21st-century politics: Digital strategy, or the use of data, new media and randomized controlled experiments to enhance a campaign's performance.

Data science can help juice donor giving, enhance the reach of viral ads and videos, and help eliminate waste and uncertainty. Other aspects of it help improve the interactions between voters and door-to-door volunteers, helping campaigns identify who's susceptible to further messaging, and what kind. Both conservatives and liberals have been vastly upping their investments in political technology ever since President Obama's reelection campaign introduced data-driven politics to the general public three years ago. Now, as Republicans have made strides of their own in Moneyballing politics, Democrats are seeking to maintain their edge. That contest is taking place largely in the background, but it's taken on added urgency with November — and, depressingly, 2016 — looming.

Every night for a week last month, teams of budding progressive activists stayed up past the witching hour to digest the complex lessons that, famously, helped put President Obama in the White House for a second term. Many had never written a line of HTML before in their lives. Soon they were cranking out e-mails to "voters" — a group of some 600 practicing political strategists — coding Web sites for their fictional candidates and responding to negative attacks from Draco Malfoy. A liberal's rendition of "Defense Against the Dark Arts," you could say.

The hands-on work is just the most visible part of what the New Organizing Institute, or NOI, claims it does with its annual boot camp. Beyond giving rookies a set of basic skills, the crash course helps develop a wider talent and knowledge infrastructure that many Democrats credit when discussing their technological gains of the last few electoral cycles.

Graduates of NOI's boot camp are everywhere (even Australia), subtly influencing the tone and the strategy of hundreds of campaigns and nonprofits at every scale. Lessons they learn in the field get fed back into NOI's pipeline, creating a cycle of learning and self-improvement that affects the wider party.

Political technology tends to make the most difference on the margins: Getting a few more people to share a candidate's Facebook status, or increasing donor rates by just a few percent. But in the aggregate, all that nudging can add up.

When George Zimmerman was acquitted by a jury in the Trayvon Martin case last year, Steven Pargett had already packed his bags to come to Washington. Pargett, a communications director for a Florida nonprofit, was bound for D.C. to attend NOI's seventh annual boot camp. But when the court's decision came down, Pargett sprung into action, putting off his new media training for a year. Reflecting recently, Pargett said staying behind to organize protests around the verdict was still the right call. But he wished he'd had the benefit of knowing then the skills he's learned now — from how to craft action-driving messages to running controlled experiments with his organization's list of 18,000 registered e-mail addresses.

"That would've led to us having better conversations with our supporters," he said. "We would've raised more money. It would've made such a huge difference."

At boot camp last month, Pargett and his teammates began each day with an in-person crash course on the left's latest tactics and techniques. Many had been honed and tested under real-world conditions in the 2008, 2010 and 2012 elections. Over time, as political technology has gotten more complex, so have the classes. It used to be, for instance, that testing an e-mail meant tweaking a subject line before sending each version to a small subset of voters — an attempt to see which subject line was better at getting people to open the correspondence. Then the winning subject line would be used in the mass mailing to a wider audience.

Even in the last few years, however, testing has become a multivariate process, said Matt Compton, digital director for the Democratic National Committee.

"Now we're talking about testing multiple drafts against each other," he said. "Some of them may be image-based, testing various senders against each other, testing various packets within the e-mail and doing all of that within one single test … The tools have given us much more capacity to do more sophisticated testing."

Practitioners like Compton dropped by boot camp to explain to trainees how all these tactics worked — but on at least one occasion, they were interrupted by actual politics.

The day NOI taught its campers about e-mail happened to be the same day as former House Majority Leader Eric Cantor's stunning loss against primary challenger David Brat in Virginia. As news of the upset spread, NOI's training room turned into a real-life campaign war-room as officials for various organizations scrambled for the doors.

"For a moment, I was like, 'This is going to ruin everything,'" said NOI training manager Bridget Todd. "But then I was like, 'Wait, this is actually a great lesson boot campers are seeing.' That visual of folks checking their phone and rushing into the nearest office? It's good."

Pretty soon, the boot campers themselves were putting what they'd learned to use. Their task: Deploy digital tactics to sell Hagrid, Professor McGonagall and a range of other characters to a group of critical experts who weren't afraid to give occasionally biting feedback on their performance.

The name "boot camp" is not undeserved. Students received their hands-on assignments each day at around dinnertime (after having already spent the day learning); few finished before 2 a.m. At that hour, relationships grew tense. One trainee, a programmer and immigrant activist named Erick Garcia, joked that there were times he wanted to kill his teammates. Others were forced to unlearn old habits, much to their chagrin.

"I thought I knew everything about writing," said Eartha Terrell, who worked on Hagrid's campaign. "When I got here, I was stripped of that ego pretty quickly."

The feedback from real-world strategists wasn't random; many, including the trainers, are themselves boot camp alumni. Boot campers have gone on to some of the most prominent left-leaning organizations in the country — such as AFL-CIO, Greenpeace and Planned Parenthood, not to mention the White House and political firms like Blue State Digital.

From perches like these, the boot camp graduates often hold two interrelated jobs: To win, and to discover new political tactics in the course of doing so.

These dual activities aren't taking place in a vacuum; Republicans are working quickly to make up for a technological shortfall that emerged during the 2012 campaign. In recent months, the GOP has debuted a set of data and analytics tools for statewide campaigns in preparation for this year's midterm elections. An early taste of the technology came in March when Republicans performed what they called a "live-fire test" in Florida. The test seemed to work, giving David Jolly a somewhat surprising win over Democrat Alex Sink. The district in question had broken for Obama in both 2008 and 2012, leading many to expect a similar outcome this time. No dice.

For the left, boot camp isn't just about teaching newbies the basics; it's about staying a few steps ahead of the Republicans and preventing more races from turning out like Sink and Jolly's. They might hang onto that technological lead for a while, according to University of Virginia political scientist Larry Sabato. But probably not forever.

"Mobilization begets countermobilization," Sabato said in an interview. "It's a fundamental principle of politics. The leadership in campaign technology often moves back and forth between the parties, often depending on which party is more desperate."

The big challenge for Democrats now, Sabato added, is in figuring out how to mobilize voters for an off-year election. Turnout, it turns out, is a longstanding puzzle when it comes to midterms. If Democrats can't close the turnout gap, they'll be likely to lose ground in Congress come November.

To help forestall that outcome, the left has been pushing its lessons about data and analytics all the way down to mayoral candidates and county council races.

This is also where boot camp alumni come in. In addition to those who take positions at high-profile political organizations, many more spread to smaller advocacy groups and campaigns. Beyond their day jobs, these digitally savvy individuals act as informal listening posts for NOI: What a same-sex marriage advocate learns in one state about tactics and technology will ultimately benefit climate activists in Vermont, and vice versa.

Boot camp has even gone global. Tabatha Fulker is an Australian organizer who came to NOI with an eye toward starting a version of boot camp back home. Australians understand that that political technology is the future, Fulker told me — but they don't know how to put it into practice. And the fancy technology and data science won't help anyone if it's too complicated to learn.

"Excel bores us all to tears and it's intimidating," said Fulker. "Unless you know how to do it, you kind of sit there and pretend. But we walked into that session and there were two people wearing party hats off the side of their heads, and they made it fun."

The fact that each year's mock election is based on its own theme helps. In past years, the candidates running for Columbia's 22nd district have taken the shape of Muppets, characters from '90s television shows and superheroes.

Personality and community, Fulker and others said, is boot camp's secret sauce. It's the foundation for a much larger network of liberals than boot camp itself can reasonably hope to train. Whereas an organization's loyalty might otherwise end at its own front door or its state boundary, NOI's created a self-sustaining organism that ties activists and organizers into a more cohesive crowd that evolves over time.

Other organizations on the left have done this kind of work before. The Analyst Institute is a low-profile clearinghouse for campaign know-how with a similar bent for data and rigorous testing. But its research is mostly secret, as are its members and relationships. AI's Web site is a barebones destination with little in the way of introductory information. Although AI was thought to have worked closely with the Obama campaign team, it wouldn't acknowledge doing so. Where NOI's general approach might be described as crowdsourcing, AI has adopted a brain-trust strategy to developing new tactics. In many ways, the Analyst Institute is more of a foil to NOI than anything else.

All that was pretty far from the minds of boot campers' after six days of campaigning. In a last-minute effort to secure uncast ballots, candidates blasted a final plea to their supporters to get out the vote.

"Tell your friends, family and even the ghoul living in your attic to get out to vote today," Luna Lovegood's digital directors wrote. Professor McGonagall announced an eleventh-hour endorsement by the Working Families Party. Joe Biden exhorted his followers to kick Death Eaters out of Congress.

By the time polls closed, it was clear who was going to represent Democrats against the Slytherin machine: Lee Jordan, the Gryffindor Quidditch commentator who was also, it turned out, an advocate for immigrants and house elves. This race was over. But the real race — the Muggle elections — has only just begun.