Why exactly is Federal Trade Commission Chair Lina Khan antagonizing Amazon.com Inc., of all companies? In a 172-page complaint announced last week, the FTC alleges that Amazon engages in "far-reaching schemes" to impede competitors. Actual evidence for these charges is scant - the document is heavily redacted - but one thing comes through clearly. In discarding its mandate to protect consumer welfare, the FTC has lost its way.

As a start, the complaint simply asserts that Amazon is an illegal monopoly. Bloomberg Intelligence estimates that the company's platform captures less than 30% of U.S. retail e-commerce sales. Its share of total retail is perhaps 5%. Multiple studies have found that Amazon is consistently the cheapest online retailer; on average, its prices were 14% lower than its competitors last year.

Only under a truly tortured definition of "market" could such numbers add up to unlawful dominance. And, sure enough, the FTC has two of them: the "online superstore market" and the "market for online marketplace services purchased by sellers." Expediently, the first definition excludes brick-and-mortar stores, specialty retailers, brand-specific sites, online grocers and other "online stores with a more limited selection"; the second doesn't count Shopify Inc., BigCommerce Inc. or other direct-to-consumer platforms. (No mention is made of thriving upstarts such as Temu and Shein.)

With Amazon's market artificially narrowed, the complaint posits a few more specific objections. In each, the FTC is wielding fringe antitrust theories with little regard for consumers.One allegation is that Amazon punishes sellers that offer products for lower prices on competing platforms. For instance, the suit says, Amazon blocks such sellers from its "buy box," which highlights what the company considers the most valuable results to a user's query. The FTC states (without evidence) that this practice leads sellers to raise their prices on other sites. Setting aside that such arrangements have never been found unlawful by a U.S. court, Amazon is guiding buyers to sellers offering the same products for less - in other words, facilitating competition. Exactly what remedy would the government impose?

The suit also takes a swipe at Amazon Prime, the discount membership service that the FTC is challenging in a separate complaint. The commission objects to Amazon's requirement that third-party sellers that want their products to be "Prime eligible" also use the company's fulfillment service. Those sellers, the theory goes, should be free to package and ship goods using whatever service they like. This gets things backward. Amazon invested billions of dollars building a shipping network to expedite Prime deliveries and build consumer confidence in the program. Why should it be forced to grant access to that service on terms that it objects to - and that might well jeopardize the trust of its customers? (Amazon says the point is moot in any event: It now allows sellers to use other services that meet its standards.)

There's a larger point to bear in mind. Prime has about 150 million members in the U.S.; fully 91% of them report being satisfied with their subscription. A recent study by JPMorgan Chase & Co. estimated that the average consumer value of a $139 annual Prime subscription is as much as $1,000. Amazon routinely ranks among the most trusted brands in the country. It invests more in R&D - $73 billion last year - than any company in the world. More pertinently: It allows consumers to search for any product they desire, select among a bevy of competing alternatives, and expect a neatly wrapped package to arrive within days (or, indeed, hours). If consumer welfare is the FTC's lodestar - as it should be - a worse target for government intervention is hard to imagine.The good news is that this case is likely to fail in court. No consumer should wish otherwise.