There are few things more powerful in politics than a dumb idea whose time has come.

This accounts for the seemingly inexorable momentum of the rallying cry, “Abolish ICE,” which has rapidly gone from fantastical left-wing cause to mainstream Democratic issue embraced by prospective presidential candidates. The great advantage of “Abolish ICE” is precisely its witless simplicity and emotive symbolism removed from any practical considerations of government.

In the wake of anti-ICE progressive Alexandria Ocasio-Cortez’s stunning upset victory in a New York City congressional primary last week, Democrats have jumped on the bandwagon, not knowing where it’s going or why. They can’t decide if Immigration and Customs Enforcement is unaccountable or too accountable to President Donald Trump. They denounce it as a “deportation force” when it’s not clear what else a government agency charged with deporting people who violate our immigration laws is supposed to be.

The roots of ICE go back 15 years and are hardly nefarious. The old Immigration and Naturalization Service handled both legal and illegal immigration. Bipartisan legislation placed the agency in the new Department of Homeland Security after 9/11, which was in part a failure of immigration enforcement, and split up its functions. ICE got interior enforcement.

Despite his erroneous reputation as the “deporter-in-chief,” President Barack Obama gutted enforcement in the interior. Trump has restored ICE to a more traditional role, although still charging it with focusing on illegal aliens who have committed additional criminal offenses. Given the enormous number of criminal illegal aliens — nearly 1 million — ICE has plenty of work. Almost all of its arrests and deportations are of people who have criminal convictions, have been charged with a crime or have been ordered removed by a judge.

During the last few weeks of June, ICE served an arrest warrant on a Brazilian man facing sex charges in Massachusetts. He will be deported after his prosecution, and had entered the country illegally once before. It deported a Liberian national who served as a bodyguard for war criminal Charles Taylor. It removed an Ecuadorian man wanted for rape, an El Salvadoran national affiliated with MS-13, and an Irish member of the “Cock-Wall Gang,” and transferred custody of them to law enforcement in their home countries.

This is not exactly fodder for protest, or is it? An ICE action in Oakland, California, last year stirred up an immediate impromptu anti-ICE protest outside the house in question. It turns out that the agents were executing a search warrant related to a sex-trafficking investigation, which presumably even Alexandria Ocasio-Cortez would support.

Assuming that Democrats support this kind of enforcement, who would carry it out if not ICE? Going back to the pre-ICE status quo would mean reuniting all immigration functions in an agency like the INS housed at the Justice Department and directly under the control of none other than Attorney General Jeff Sessions.

That’s a non-starter. So the Democratic plan is to ax a major law-enforcement agency and figure out the rest later. The House bill to abolish ICE calls, per the press release, for “a commission to provide recommendations to Congress on how the U.S. government can implement a humane immigration enforcement system.”

Progressives would surely hate ICE’s replacement in turn. Once upon a time, immigrant advocates lodged all the same charges at the INS that they now make against ICE. That’s because at the end of the day, their problem is with enforcement as such, rather than any particular bureaucratic configuration of immigration agencies.

One way to ramp up enforcement without increasing deportations would be an e-verify system that required employers to reliably verify the legal status of workers — but Democrats oppose that, too.

“Abolish ICE,” whatever its power as a slogan on the left, is almost surely bad politics. It’s as if during the ferment over Black Lives Matter, Democrats came out for abolishing police departments and starting over – consequences be damned.