Abolish ICE!

That was the seemingly radical message that Chardo Richardson, a House candidate in Florida, published in an online statement four months ago, endorsing a call to eliminate the Immigration and Customs Enforcement agency.

“Immigrants are some of the most courageous and industrious people humanity has to offer,” he wrote in an introduction to the immigration platform of Brand New Congress, a grass-roots progressive organization. “We can only benefit from their presence.”

To that point, the idea had largely been passed around on social media; among political candidates, Mr. Richardson was something of a lonely voice. But in the months since — as startling images emerged from the border of migrant children separated from their parents — the call to abolish or defund the agency has gained momentum in the midterm campaigns. Case in point: the shocking victory on Tuesday by an insurgent primary candidate in New York, Alexandria Ocasio-Cortez, who had made abolishing ICE a part of her platform.

From Massachusetts to Hawaii, progressive candidates undeterred by the immense obstacles to eliminating a federal agency have peppered Twitter with hashtags of support. Deb Haaland, a Native American who stunned the New Mexico political establishment with a House primary victory early this month, supports the idea. A Florida candidate, Matt Haggman, cut a campaign ad promising to “close ICE down.” Cynthia Nixon, who is running for governor in New York, has called the immigration agency a “terrorist organization.”