Who knew that draining the swamp would mean ousting experts?

Once upon a time, President Trump pledged to “drain the swamp.”

This resonated with lots of Americans, who resented the ecosystem of interest groups rigging government in their favor: corrupt officials, revolving-door lobbyists, palm-greasing executives and the network of pseudo-think tanks and analysts funded by industries trying to pass off propaganda as impartial research.

At last, the mystery of this apparent broken swamp-drainage promise has been solved. Turns out what Trump and his cronies meant by “the swamp” wasn’t regulatory parasites or crooked officials, but experts.

When the Forgotten Man expressed rage at “swamp creatures,” he probably wasn’t envisioning civil servants with subject-matter expertise — career diplomats who speak Persian, say, or scientists who evaluate water quality. And yet the Trump administration has celebrated brain drains at the State Department, the Environmental Protection Agency, the Consumer Financial Protection Bureau, and other agencies and advisory councils.

The latest, most egregious example involves the Economic Research Service, an independent statistical agency at the Agriculture Department.

The small-but-mighty ERS is arguably the world’s premier agricultural economics agency. It produces critical numbers that farmers rely on when deciding what to plant and how much, how to price, how to manage risk; and that other stakeholders and public officials use to evaluate agricultural policy.

However, because it is independent, the ERS produces research that the Trump administration sometimes finds inconvenient, such as who has really been helped by his tax cuts, how climate change might affect agriculture or how his trade wars hurt farmers.

The administration’s solution to these inconveniences? Blowing up the agency altogether.

In June, the Agriculture Department informed employees at the ERS and the National Institute of Food and Agriculture, which manages $1.7 billion in scientific funding, that they were moving to “the Kansas City Region,” precise location TBD. Employees had 30 days to decide whether to uproot their families or lose their jobs.

As of July 26, only 116 employees agreed to relocate, according to a USDA spokesperson. That’s about 20 percent of those initially asked. The Trump administration is celebrating.

“You’ve heard about ‘drain the swamp,’” acting White House chief of staff Mick Mulvaney said to cheers at a Republican Party gala last week, while recounting the departures of scientists, statisticians and economists. “What you probably haven’t heard is what we are actually doing.”

Mulvaney’s comments, alas, have caused some problems for the USDA, which officially justified the abrupt move as a way to “attract and retain” talent, be closer to “stakeholders” and reduce costs by moving to a less expensive city.

Days after Mulvaney’s remarks, a new report from the USDA’s inspector general found the move might have violated budget law (since Congress never appropriated relocation funds) as well as internal department regulations.

The many departures also look likely to leave the ERS unable to produce reports required by statute.

Again, maybe that’s the goal. “We do research that’s apolitical, unbiased, comprehensive, good-quality,” an ERS employee told me, under condition of anonymity due to fears of retaliation. “When we’re not there, Congress relies on other sources of information — think tanks and lobbyists, whoever’s got the biggest donor. That’s who they listen to because there’s no authoritative source for them to go to.”

In other words, who benefits from draining the fake “swamp”? The real one.