Since President Trump’s election, his loyalists online have provided him with a steady stream of provocative posts and shareable memes, often filtered up from platforms like Reddit through media channels like Fox News. In return, Mr. Trump has championed many of their messages as his own, amplifying them back to his larger base.

This feedback loop is how #JobsNotMobs came to be. In less than two weeks, the three-word phrase expanded from corners of the right-wing internet onto some of the most prominent political stages in the country, days before the midterm elections.

On Oct. 11, a video went viral on Twitter. The clip alternated between footage of angry protesters and clips of cable news anchors discouraging the use of the word “mobs” to describe those activists. The “mob” depiction is rooted in the right-wing talking point that Republicans are the rational alternatives to violent left-wing protesters, like the so-called anti-fascists who clashed with far-right groups last year. Soon after the “supercut” video went viral, the phrase “jobs not mobs” began gaining momentum. The “jobs” part of the phrase refers to the record low unemployment and job growth in the United States, for which Mr. Trump has taken credit. Scott Adams, the creator of the “Dilbert” cartoon strip, quickly endorsed “jobs not mobs” as a potential slogan. Because of the cartoonist’s popularity among the pro-Trump crowd online, this was a key moment. A screenshot of Mr. Adams’s tweet was posted to Reddit, followed by a meme with the phrase laid over an image of factory workers at the top and a violent protest at the bottom. “This meme can go far,” one Reddit user wrote. The creator of the meme, who goes by the pen name “Bryan Machiavelli,” told The New York Times he charges $200 an hour for his “memetic warfare consulting” services. Users on Reddit and Twitter continued to push the slogan, as popular pages on Facebook began to pick it up. The transfer of a message across social networks is one way a meme like this becomes amplified.

Over the following days, #JobsNotMobs was used in reference to everyone from liberal protesters to Central American migrants trying to come into the United States.

The phrase was pushed by a series of increasingly prominent conservatives who have often railed against anti-fascist protesters. James Woods, the actor, tweeted it on Oct. 13. The next day, Charlie Kirk, a pro-Trump activist with a large internet following, sent it out. Women for Trump Movement, a Facebook page, wrote about it in a post that was shared 1,200 times.

Conservative media outlets routinely pick up stories that are gaining traction on the pro-Trump internet, and #JobsNotMobs was no exception. On Oct. 15, “Fox & Friends” aired a segment on the phrase, saying: “The Trump administration is focusing on what Americans really care about. Not mobs, but jobs!”

Soon, Republicans around the country were racing to feature #JobsNotMobs in campaign materials.