The House wants to talk to Bezos, who acquiesced to attend only after the threat of a subpoena, according to the New York Times, over concerns about Amazon’s dominance of e-commerce, its expansion into other businesses like physical grocery stores that may stifle competition, and its acquisition of would-be competitors. Amazon is under particular scrutiny for alleged misuse of its powerful platform to give its own products an edge against third-party sellers.

Based on those concerns, critics say that Amazon should be subject to antitrust action, which could include fines or, at the most extreme, a forced spinoff of parts of the company.

No House hearings are currently scheduled, but if and when they are, Bezos could be joined by representatives from Google and Facebook, who have also faced criticism on antitrust grounds.

In addition to antitrust, a number of other issues are likely to come up during a hearing. Unions complain that Amazon’s dominance of the labor market depresses wages in areas where it operates and about its treatment of warehouse workers during the coronavirus pandemic. Additionally, Amazon’s avoidance of corporate taxes is a frequent target.

If he ends up testifying, Bezos would need to convince Congress, and the public at large, that Amazon benefits consumers and that those benefits would be less if members clipped its wings. Antitrust regulators focus primarily on the harm powerful companies cause to consumers, though there is rising concern that the standard is not broad enough to include all the harms that Big Tech causes.

One likely talking point for Bezos is that while Amazon dominates e-commerce with a 44% market share, its share of all U.S. retail is much lower at around 6%, according to one recent analyst estimate. In other words, if a consumer doesn’t like Amazon, they have plenty of other options, online or off.

The company has faced antitrust pressure from a variety of agencies and governments in the past. The U.S. Department of Justice launched a broad antitrust probe of big tech companies last year, with the department’s antitrust lead Makan Delrahim alluding to Amazon in describing big tech companies as “digital gatekeepers” with few competitors.

The Federal Trade Commission has taken charge of the portion of the probe that is focused on Amazon. That has included interviewing small merchants about their dependence on the company.

Just last week, the European Union was reported to be planning formal antitrust charges against Amazon. Those charges would reportedly focus on Amazon gathering data from third-party sellers on its platform, then using that data to compete against the sellers, including by launching its own products. Judiciary Committee chairman Jerrold Nadler (D-N.Y.) had previously expressed “deep concern” over reports of those practices, making them a likely major focus of any hearing.

Bezos could be hit with a different, perhaps even more uncomfortable set of questions from Republican committee members loyal to President Trump. For years, Trump has lobbed a variety of accusations at Bezos and his company, including that it has underpaid for delivery from the U.S. Postal Service.

Trump’s attacks on Amazon may be motivated by Bezos’s ownership of the Washington Post, which has frequently published unflattering articles about the President. Amazon has even alleged that Trump’s animus led the President to interfere with the bidding for a $10 million cloud-services contract, for a program known as JEDI, from the Department of Defense.

At least three members of the House Judiciary Committee—Matt Gaetz, Louie Gohmert, and ranking minority member Jim Jordan—are prominent Trump advocates. They could use a high-profile hearing to air the President’s attacks again or even go after Bezos’s influence over the Post’s coverage. Bezos has been largely restrained in his response to the President’s complaints, and he may take a similar tack in hearings.