“Price gouging” is the focus of Vice President Kamala Harris’s economic agenda, her presidential campaign says. She’ll crack down on “excessive prices” and “excessive corporate profits,” particularly for groceries.

So what level counts as “excessive,” you might ask? TBD, but Harris will ban it.

That’s the thing about price gouging: As has been said of hardcore pornography, you know it when you see it.

It’s not hard to figure out where this proposal came from. Voters want to blame someone for high grocery bills, and the presidential candidates have apparently decided the choices are either the Biden administration or corporate greed. Harris has chosen the latter.

In a news release Wednesday, her campaign said the first 100 days of her presidency would include the “first-ever federal ban on price gouging on food and groceries — setting clear rules of the road to make clear that big corporations can’t unfairly exploit consumers to run up excessive corporate profits on food and groceries.”

What are these “clear rules of the road” or the thresholds that determine when a price or profit level becomes “excessive”?

The memo doesn’t say, and the campaign did not answer questions I sent seeking clarification.

The most likely template for Harris’s proposal is a recent bill from Sen. Elizabeth Warren (D-Mass.). (Harris co-sponsored similar legislation with Warren in 2020, when Harris was a senator.) Warren’s bill would ban any “grossly excessive price” during any “atypical disruption” of a market.

Alas, no definition was provided for these terms, either; rather, the bill would empower the Federal Trade Commission to enforce bans using any metric it deems appropriate.

It’s hard to exaggerate how bad this policy is. It is, in all but name, a sweeping set of government-enforced price controls across every industry, not only food.

Supply and demand would no longer determine prices or profit levels.

Far-off Washington bureaucrats would. The FTC would be able to tell, say, a Kroger in Ohio the acceptable price it can charge for milk.

At best, this would lead to shortages, black markets and hoarding, among other distortions seen previous times countries tried to limit price growth by fiat. (There’s a reason narrower “price gouging” laws that exist in some U.S. states are rarely invoked.)

At worst, it might accidentally raise prices.

That’s because, among other things, the legislation would ban companies from offering lower prices to a big customer such as Costco than to Joe’s Corner Store, which means quantity discounts are in trouble. Worse, it would require public companies to publish detailed internal data about costs, margins, contracts and their future pricing strategies.

Posting cost and pricing plans publicly is a fantastic way for companies to collude to keep prices higher — all facilitated by the government.

Price-fixing is already illegal. And it should be! It’s important to distinguish between real cartel behavior (whether among TV-makers or meatpackers) vs. temporary spikes in prices and profits due to high demand or supply-chain disruptions.

Harris’s economic advisers are either too confused or lazy to tell the difference.

They don’t seem to know the history of these kinds of policies and apparently haven’t thought very hard about what would make markets more competitive or improve the lives of voters.

They don’t even seem terribly familiar with what’s happening to grocery prices, where the battle against inflation has, believe it not, pretty much already been won.

On Wednesday, a government report showed that grocery prices in July were up a measly 1 percent from last year, as the White House itself touted.

Indeed, annual grocery price inflation has hovered around that level for the past eight months, way down from the double-digit inflation in mid-2022.

Additionally, profit margins for supermarkets are notoriously thin. Despite Harris’s (and Warren’s) accusations about “excessive corporate profits,” those margins remained relatively meager even when prices surged.

The grocery industry’s net profit margins peaked at 3 percent in 2020, falling to 1.6 percent last year.

So what actually happened with grocery inflation, if not “price gouging” (however defined)?

Superstrong consumer demand plus major supply disruptions (the coronavirus pandemic, bird flu, Russia’s invasion of Ukraine, etc.) pushed prices and profits up. Once those shocks abated and consumers started spending down their pandemic savings, price growth cooled.

These are the kinds of facts the Harris campaign should be explaining to consumers, not exploiting for demagogic gain because push-polling suggests people are mad about “greed.”

But more to the point: If your opponent claims you’re a “communist,” maybe don’t start with an economic agenda that can (accurately) be labeled as federal price controls.

We already have plenty of economic gibberish coming from the Republican presidential ticket. Do we really need more from the other side, too?

Catherine Rampell is a Washington Post columnist.