The essay, written by a law student named Lina Khan, argued, essentially, that the current framing of the nation’s antitrust laws have not evolved to deal with the market power of technology giants like Amazon.

Just a few weeks earlier, The Capitol Forum, a Washington, D.C.-based news service that examines business and regulation, published a story arguing Amazon risked antitrust enforcement by the Trump administration for using its algorithms and platform to promote its own products over “those of merchants that are dependent on Amazon’s platform and with whom Amazon competes.”

The articles fed into a growing debate among economists and lawyers around whether Amazon is displaying monopolistic or anticompetitive behavior in its marketplace.

Amazon has two strong defenses when these issues are raised.

At least since the 1970s, courts have been very skeptical of antitrust plaintiffs who can’t show that the challenged conduct would cause prices to go up or quality to go down. In this case, Amazon can argue, quite vehemently that, through its platform, consumers are paying lower prices, say legal experts.

And while Amazon’s brands have quickly gained market share on its platform in some areas, in other segments, such as apparel, they account for less than 1 percent of the inventory sold. And when broadened out to include brick-and-mortar stores, its online share of the battery market equals less than 5 percent. Until Amazon’s share of the total market starts to reach closer to 40 percent or more, it is difficult to argue there is an attempted-monopolization case, say legal experts.

But if its private-label business grows as analysts expect it to do, could it face a legal challenge of whether it is a “monopsony”? In a monopsony, a large buyer controls a large proportion of the market and drives prices down.

“If Amazon is not making its competitors available on voice and Alexa, well, that sounds like possible exclusionary conduct to me,” said Mr. Sagers. “If a federal court could be convinced that there is a market for in-home, voice retail distribution and that Amazon controls it, then I think Amazon could be looking at a monopsony case.”