WASHINGTON — They're here. They vape. And they say they'll vote you out of office if you come for their "unicorn poop" flavored vape juice.

Facing a perfect storm of threats from federal, state and local governments, vapers are banding together politically to defend a product that they claim saves lives and that has created a livelihood for some and way of life for others.

As the Trump administration prepares to roll out new rules as soon as this week on vaping in response to an alarming rise in teenage e-cigarette use and health concerns, hundreds of adult vapers gathered outside the White House on Saturday. They were there to convince people that President Donald Trump could lose his re-election if he alienates a growing constituency that is only just now becoming politically active.

"If Trump bans flavors, there's a good chance he loses Wisconsin, Michigan, Pennsylvania, Ohio, Florida," said Ryan Hallisey, from Orange County, N.Y., a vape store owner who took part in the demonstration. "He won those so narrowly, and so many vapers, like 80 percent, are single-issue voters."

The "vape lobby" and its grassroots foot soldiers have been flooding the White House switchboard with calls. They've posted tens of thousands of testimonials on social media and they've rallied at state capitols to let politicians know #WeVapeWeVote, as their hashtag reads.

Some have argued there are enough vapers to potentially sway the 2020 election.

Paul Blair of Americans for Tax Reform estimated, based on FDA data on vape users and election turnout numbers, that there are 900,000 vapers who will vote next year in Florida, a state Trump won by less than 113,000 votes. And it's a similar story in other swing states like Michigan and Wisconsin.

And vapers say they've already helped win elections for allies — Sen. Ron Johnson, R-Wis., thanked e-cigarette users during his election night rally in 2016 and who has more recently urged Trump to go easy on them. "You made tonight possible; I truly appreciate it. I will be on your side," he said upon winning re-election.

Any other industry would love to have consumers as passionate as vapers.

Travis Rush, 28, of Indianapolis, wears a "Let America Vape Again" hat at the rally. Justin T. Gellerson / for NBC News

Seventy-three percent of vapers said they would be "much less likely" to vote for a politician who supports strict regulations on vape products, such as a prohibition on internet sales, and most said they would be willing to cross party lines to do it, according to a poll commissioned by a vape industry group.

Nearly a quarter of regular vapers, the poll found, would be likely to vote for a third-party candidate in the next election — the Libertarian Party owns the url vape.vote and sells vape merchandise — while 43 percent aligned themselves with the GOP and 35 percent with Democrats.

"It's normally very difficult to get people impacted by a stupid tax or stupid law to show up and protest," said Blair of the Grover Norquist-led anti-tax group that often tries but rarely succeeds to build mass mobilizations against government action. "I couldn't manufacture this kind of opposition."

Blair compared vape politics to gun politics. While cracking down on vaping may poll well with Americans overall, the vast majority of voters will not go into the voting booth thinking about a candidate's stance on vaping. But vapers will.

While the public health debate is driven by concerns about teenagers using disposable e-cigarettes like Juuls and the recent spate of acute lung diseases (the CDC said Friday that vitamin E oil in black-market marijuana vape products were to blame for at least some of the cases), "vapetivism" is driven by adults who tend to use the larger, refillable vape devices purchased at vape stores, where a sub-culture has sprouted.

According to the industry, roughly 10,000 vape stores, mostly of the mom-and-pop variety, supporting 90,000 jobs, have sprung up across the country — tobacconists, which include vape shops, were the fastest-growing retail sector in the past decade. Vape shops are now often some of the few retail storefronts left in the deserted main streets of struggling communities.

A small but committed base can be politically powerful. It looks even powerful enough to scare Trump campaign manager Brad Parscale, who raised his political concerns about the administration's proposed vape crackdown, according to the Washington Post.

A pro-vaping rally on the National Mall in Washington on Saturday. Justin T. Gellerson / for NBC News

It might be enough, in fact, to get Trump to walk-back his initial support for a ban on flavored vaping products in favor of raising the age to limit on tobacco products from 18 to 21 and limiting the sale vape of products to vape stores — positions the vape industry is OK with.

"You know, there are some pretty good aspects," Trump told reporters Friday of vaping, "including jobs, frankly."

Beatty Barnes, an actor from Virginia Beach who works at a vape shop on the side and attended the rally in D.C., said, "It sounds like with Trump, someone kind of got in his ear...He pumped the brakes. He had to."

Democratic presidential candidates have praised a potential crackdown on flavored vape products, even though vaptivists note the contenders also support cannabis legalization and have expressed no concern with flavored THC products, like gummy candies, that could appeal to kids.

Ultimately, vaptivists are hoping Trump will cast himself as their hero by declaring that the FDA will leave flavored vapes alone.

"If he came out today saying everything is OK, we'd have 3,000 MAGA hats tomorrow," said Greg Conley, the president of the American Vaping Association, over lunch at a steak house in Washington.