While lawsuits against Google and Facebook crawl their way through the courts, a second front in Washington's war on Big Tech is heating up, as legislators zero in on ways to draft new antitrust laws that take into account the unique traits of digital markets.

Driving the news: House lawmakers on the Judiciary Committee's antitrust subcommittee will grill experts and witnesses Thursday in an effort to chronicle the alleged monopolistic practices of "gatekeeper" tech companies — a prelude to drafting new laws to rein them in.

• Thursday's hearing is not a splashy one with tech CEOs. Rather, witnesses will include advocates, economists and companies like Mapbox who say they've been mistreated by Big Tech firms.
• The committee plans to wrap up a trio of hearings in March and roll out legislation soon after, subcommittee chairman Rep. Cicilline (D-RI) told Axios.

What they're saying: "[The hearing] won't focus on any one big platform specifically but the general nature of their size and how they're able to keep competitors out of the marketplace," Rep. Ken Buck (R-Colo.), ranking member of the antitrust subcommittee, told Axios.

• Companies like Amazon, Facebook and Google have "benefitted tremendously" from gaps in antitrust law, Buck said.
• "There's an increasing recognition that we need to address these issues in a way that asserts our authority... Courts have taken over legislating in this area, and it's a mistake," said Buck.

Some groups appear especially poised to pounce on Amazon and the power it holds in the e-commerce market. The National Association of Wholesaler-Distributors wrote to committee heads ahead of the hearing, urging action against Amazon's "monopolistic treatment of its third-party sellers."

• The Computer and Communications Industry Association, whose members include Amazon, Google and Facebook, urged lawmakers to show restraint.
• "U.S. antitrust policy has produced a thriving, innovative tech sector," CCIA president Matt Schruers said. "While it is always worth looking at whether regulations are working well for consumers, scrutinizing only one sector loses sight of broader market dynamics."

Where it stands: This hearing marks the new Congress' return to the tech fray after last July's hearing with CEOs from Apple, Amazon, Facebook and Google and sweeping reports following a year-long antitrust investigation.

Catch up quick: Google, Amazon, Facebook and Apple all face major antitrust actions.

• Google: The company has responded to the joint lawsuit by state attorneys general and the Department of Justice, denying allegations of wrongdoing, and attempted to move a lawsuit by Texas over advertising technology to California. Google and DOJ lawyers continue to hash out case details in status hearings.
• Facebook: Facebook has called the FTC's suit "revisionist history" and said it will fight it in court. In the meantime, it has ramped up its fights with Apple over the App Store, accusing the phone giant of monopolistic behavior.
• Apple: The DOJ is looking into Apple's control of the App Store and other practices — including, per a report in The Information, its implementation of the "Sign in with Apple" button. Meanwhile, Apple is also defending itself against claims from Facebook and gaming companies like Epic that its App Store practices are unfair to consumers and developers.
• Amazon: The FTC and state attorneys general are investigating Amazon's online marketplace, Bloomberg reported last summer.

What's next: The next hearing will be on tech monopolies' impact on the news industry, said Cicilline, followed by a hearing on modernizing current antitrust law.

• Sen. Amy Klobuchar (D-Minn.), head of the Senate Judiciary antitrust subcommittee, has told Axios she supports the House's antitrust work and recently introduced her own tech antitrust bill.
• Merrick Garland, President Biden's pick to lead the DOJ, said in congressional testimony this week the department's suit against Google would continue and he plans to take enforcement seriously.

Yes, but: The two parties have different beefs with tech, and drawing up new laws that can pass an evenly divided Senate will be tough.