Pokémon Go, the massively successful location-based augmented reality game, has barely been out a week, but Hillary Clinton’s campaign is already using it as a campaigning tool:

Hillary: "I don’t know who created Pokemon Go but I’m trying to figure out how we get them to Pokemon Go to the polls!!" -crowd cheers- — Betsy Woodruff (@woodruffbets) July 14, 2016

The game, which came out on July 6, encourages users to walk around and visit PokéStops where they can acquire items for the game like Poké Balls, and "gyms" where they can fight against other players. PokéStops and gyms are real locations in the real world. For instance, there’s a gym on a small traffic island by the Vox DC offices, and the Embassy of Iraq is a PokéStop and a reliable source of Poké Balls.

So campaign organizers for Clinton, like her Ohio organizing director Jennifer Friedmann, started showing up at PokéStops and gyms to register Pokémon Go players to vote:

Gotta Reg 'em all! @PokemonGoHub is the best thing to happen to voter registration ever #OHHillYes #TeamAthens pic.twitter.com/TnE6YLjLcp — Jennifer Friedmann (@friedmannj) July 12, 2016

The Cincinnati Enquirer's Mallorie Sullivan reports that Clinton's Ohio staff spent the past weekend going "from Cuyahoga to Athens to seek out players in their communities to register them to vote."

There’s even an official Hillary event scheduled in Lakewood, Ohio, pegged to the game. "Join us as we go to the Pokestop in Madison Park and put up a lure module, get free pokemon, & battle each other while you register voters and learn more about Sec. Hillary Clinton!!!" the event description says. "Kids welcome!"

Lure modules, for context, are items in the game that attract a large number of Pokémon to a given area. You can acquire them for free, but to use them for any length of time usually requires shelling out for additional lures, meaning the Clinton campaign could be spending funds on attracting Pokémon (and players) to its events.

Pokémon Go is the perfect campaign app

The ease with which Clinton’s campaign flocked to Pokémon Go is partially an indication of how perfect the app is as a campaign tool. Campaigns have invested considerable time and money into mastering social media platforms like Snapchat, Twitter, and Facebook, but the payoff is uncertain. If you send a funny tweet, that might win your campaign a good press cycle — but does it actually sway public opinion? Does it actually increase your odds of victory? The path to impact is so windy and indirect that evaluating whether your strategy is actually working is extraordinarily difficult.

That’s largely because those apps are not well-positioned to spur action outside their confines. Liking a tweet or sharing a Facebook post shows up as progress on the campaign’s metrics, but whether it translates into more votes is uncertain. Indeed, some experimental evidence suggests Facebook ads are ineffective at changing voters’ favorability ratings of candidates.

Pokémon Go, by contrast, is explicitly designed to move players to action in real life. You have to walk to PokéStops to get supplies. You have to walk around to run into Pokémon you can catch. That makes it a great way to lure people into robbery traps, but it also makes it a great way to lure people into voter registration drives. That intrinsic connection to physical activity makes it much easier to assess its impacts on concrete electoral outcomes.

The Clinton campaign already has actual people it’s registered to vote as a result of its Pokémon strategy. That’s a specific, important metric that you can’t measure the same way on, say, Snapchat.

The Clinton campaign’s eagerness to use an app to organize the same week it comes out is also an indication of the importance of on-the-ground field organizing. This sort of thing only works if you have field staffers on the ground to organize it, and who can do so without reducing the campaign’s ability to canvass, phone-bank, and engage in the other routine, necessary field activities. And Clinton had almost 700 people on staff already as of May's Federal Election Commission filing.

Trump, by contrast, has only 70, many of them national staff. He’s at a big, big disadvantage when it comes to field work. It’s not just Pokémon Go: Trump’s staffing disadvantage means less contact with voters, and less registration, through any number of mechanisms. And at least when it comes to registration drives and get-out-the-vote operations, there’s good experimental research showing that well-done canvassing really does work.

That disadvantage of Trump’s may or may not be reflected in his current polling deficits, but unless he staffs up dramatically, and quickly, it’ll make a big difference in November.