It wasn’t quite “build the wall” or “lock her up,” but “drain the swamp” was a signature Donald Trump slogan.

It evoked visions of pinstripe-suit-wearing influence peddlers getting pulled from their Georgetown cocktail parties en masse and tossed into the Potomac River, as Washington returned to the once-sleepy burg it was 100 years ago, a humbled and more righteous town.

This was always a fantasy. The oldest story in Washington is a new president elected on a pledge to clean up Washington, who then turns to practiced Washington hands and well-connected financiers to help shepherd his administration. It was true of George W. Bush and Barack Obama, and now will be true of the even more populist and anti-Washington Donald Trump.

The swamp will endure; it always does. This doesn’t mean that a Trump administration can’t make the swamp a little less important.

The meaning of “drain the swamp” is pleasingly inexact (Ronald Reagan used the phrase, and so has Nancy Pelosi). The left has, absurdly, chosen to read Trump’s use of the slogan as an implicit pledge not to hire anyone who is wealthy. So the nominations of Steven Mnuchin as treasury secretary, Wilbur Ross as commerce secretary and Betsy DeVos as education secretary are criticized as proof Trump never meant it.

But Trump obviously didn’t intend to impose a wealth test on his administration, or he would have failed it himself. He is proof that a fortune isn’t necessarily an obstacle to being a champion of an agenda of populist reform.

(Although the charge against Mnuchin, who worked for Goldman Sachs for 17 years, has more force. The job of treasury secretary almost seems to be the endowed Goldman Sachs chair of the U.S. government. And you could be forgiven for thinking candidate Trump had a dim view of anyone associated with Goldman, given how he excoriated Ted Cruz — “puppet!” — for his connections to the institution.)

Trump’s formal anti-swamp platform consists of a few more strictures on lobbyists. These proposed rules may be salutary, but they are typical of restrictions periodically imposed in Washington and that lobbyists are expert at getting around and surviving. (What are lobbyists for, if not finding loopholes?)

The fact is that in a country with an enormous federal government and a First Amendment that guarantees the right to petition the government, the swamp is always going to be extensive and miasmic. As long as there is so much power and money in D.C., the lobbyists, the consultants, the associations, the media pooh-bahs, the contractors and the courtiers will gather and jockey for influence here. There is no neutron bomb that can be set off to vaporize them.

A proper anti-swamp agenda should consist of two things. First, and most fundamentally, it should seek to reduce the size of the federal government, and cut regulations and make them as simple as possible. The more government does, the more incentive every special interest has to hire swamp creatures, for both protection and advantage. And the more complex government is, the more opportunity those creatures have to thrive in niches unknown or poorly understood by everyone except insiders.

Second, and more specifically, the federal government should be wrenched out of its cozy relationship with large, established businesses and institutions in areas ranging from health care to finance to education.

This agenda would have the advantage of uniting the conservatives (whose animating passion is reducing the size of government) and the populists (whose animating passion is combating a “rigged” system). A number of Trump’s Cabinet picks point in this direction. But it’s not clear where Trump will ultimately go. If he replaces Obama’s liberal industrial policy focused on green energy with his own populist industrial policy focused on traditional manufacturing, as suggested by the Carrier deal, he will just spend and subsidize in different ways.

In other words, he won’t truly drain the swamp, but simply feed different alligators.

Rich Lowry can be reached via e-mail: comments.lowry@nationalreview.com.