It is an axiom of modern American life: Offer a new service that is wildly popular with the public, and sooner or later you will find yourself labeled an enemy of the people.

The latest target is Uber, the app-based ride-sharing service that since its launch in San Francisco just five years ago has expanded to more than 300 cities across the globe. Here in New York, Uber is now locked in combat with the city’s progressive mayor, Bill de Blasio. In a Sunday op-ed for the Daily News, Mr. de Blasio said he aims to freeze Uber’s expansion until his regulators can figure out how best to block any attempts to “skirt vital protections and oversight.”

The mayor’s call to arms comes only days after Hillary Clinton used her big speech on economics to sound a similarly dismal note. Though she didn’t mention Uber by name, the Democratic Party’s leading contender for the 2016 presidential nomination fretted that while the “gig economy” may be “exciting” and “unleashing innovation,” “it is also raising hard questions about workplace protections and what a good job will look like in the future.”

Hard questions that Mrs. Clinton no doubt intends the government to answer, even if those answers end up making Uber and others like it less exciting and less innovative.

Republican presidential candidates are having fun with all this. Marco Rubio, who last year sided with Uber over regulators in Miami, accused Mrs. Clinton of trying to “regulate 21st-century industries with 20th-century ideas.” Jeb Bush pointedly traveled by Uber for his visit to Thumbtack, a Silicon Valley startup. Meanwhile, Rand Paul says he would like our government to adopt the Uber model—more information and customer ratings—while Ted Cruz says his campaign will be as disruptive of politics-as-usual as Uber is of old business models.