Two Democratic senators now support a bill to ban the sale of loot boxes to children, giving the measure bipartisan support after Sen. Josh Hawley (R-MO) proposed it two weeks ago.

Under the Protecting Children from Abusive Games Act, video games that are marketed to children would be prohibited from implementing any pay-to-win mechanisms. All games would be forbidden from selling loot boxes to children. In statements yesterday, Sens. Richard Blumenthal (D-CT) and Sen. Ed Markey (D-MA) endorsed Hawley’s bill.

“Congress must send a clear warning to app developers and tech companies: Children are not cash cows to exploit for profit,” Blumenthal said.

Hawley will formally introduce his bill today; he and Blumenthal have previously worked together to make changes to the Children’s Online Privacy Protection Act of 1998 (COPPA). Both senators have prosecutorial backgrounds as the attorneys general in their respective states.

Markey has served in Congress since 1976. “Today’s digital entertainment ecosystem is an online gauntlet for children,” he said. “Inherently manipulative game features that take advantage of kids and turn play time into pay time should be out of bounds.”

Under Hawley’s bill, a publisher or developer would face fines for including these features in children’s games, or allowing kids under 18 to use them in any game. Hawley has said his bill will reference COPPA in determining whether a game is aimed at children, but that may be harder than it sounds as the law seems to take that on a case-by-case basis, expecting operators to self-enforce most of its provisions.

Loot boxes attracted lawmakers’ notice when several controversies involving their use — most notably Star Wars Battlefront 2’s original economy — boiled up in late 2017. State lawmakers in Hawaii were the first in the U.S. to propose legislation restricting or banning loot boxes, but that effort went nowhere.

Regulators in New Zealand and Belgium also investigated loot boxes, with Belgium determining that Overwatch’s loot boxes constituted a form of gambling. Blizzard disagreed with the ruling, but pulled them from sale in that country. No legislation was introduced in either case.

The video game ratings boards for Europe and North America last year required titles with in-game purchase systems to label themselves accordingly. Two weeks ago, the Entertainment Software Association, which set up the Entertainment Software Ratings Board 25 years ago, referenced numerous nations’ findings that loot boxes aren’t gambling while arguing that existing self-regulations are adequate to protect minors.

In an interview with Kotaku earlier this week, Hawley and a policy advisor said they had been in contact with the ESA and with Electronic Arts, whose enormously popular Ultimate Team mode in the FIFA series would be covered by Hawley’s bill. Hawley implied that those discussions had been sharp.

“And FIFA would indeed be covered by this legislation, to be clear,” Hawley told Kotaku. “[EA has] certainly expressed their, shall we say, concern over this legislation. But I think that’s probably a good indication that we’re getting somewhere.”

The Verge noted on Thursday that Sen. Maggie Hassan (D-NH) has yet to co-sign the bill. In a Senate committee hearing last November, Hassan called on the Federal Trade Commission to investigate loot boxes, calling them a “close link” to gambling and saying children were particularly susceptible to them. The FTC agreed to Hassan’s request.

Update: The ESA provided this statement, regarding Hawley’s bill, from Stanley Pierre-Louis, the association’s chief executive: