Auto racing champion Mario Andretti arrives for a press conference outside the U.S. Capitol on Wednesday, May 1, 2024, to make the case for admitting Andretti Cadillac to the Formula One grid. Bill Clark | Cq-roll Call, Inc. | Getty Images

Twelve members of the U.S. Congress sent a letter to Formula 1 owner Liberty Media on Wednesday demanding answers for why it is excluding Andretti Global from the sport, giving the American team powerful new allies in its bid to enter F1.

The bipartisan group of lawmakers said they have "concerns with the apparent anti-competitive actions that could prevent two American companies, Andretti Global and General Motors (GM), from producing and competing in Formula 1."

They invoked the Sherman Antitrust Act of 1890 and sought answers for the rationale for rejecting the team, including whether it is designed to unfairly protect the European teams from competition in the U.S., where the fan base has grown dramatically.

Andretti has partnered with GM and Cadillac to produce engines for its team, giving the Michigan-based auto giant and its workers a stake in the outcome of the decision. The letter was led by Rep. John James, R-Mich., who represents a competitive district in Michigan, and signed by several lawmakers in the state, among others.

"It is unfair and wrong to attempt to block American companies from joining Formula 1, which could also violate American antitrust laws," they wrote to Liberty's President and CEO Gregory Maffei.

Mario Andretti, a former Formula 1 world champion, joined lawmakers for a press conference Wednesday outside the U.S. Capitol to make his plea — again — for competing in the sport. He argued his team has fulfilled all the requirements but that it hasn't been enough for F1's owners.

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"We're ready with everything that's needed. Give us a green light and let us do our thing," Andretti said. "Our team, Andretti Global, is part of every major racing discipline in the world. … Formula 1 is the one that's left. And we want to be part of that."

"We have all the passion and resolve necessary," he said.

Andretti's bid is currently in limbo. Last fall Formula 1's governing body, the FIA, accepted the racing team's push to join the grid, saying it met the criteria. But the sport's commercial arm, Formula One Management, which is influenced by the 10 teams currently on the grid, has since denied Andretti entry, arguing that it cannot be competitive in either 2025 or 2026.

James accused the F1 owners of engaging in "cartel-like behavior."

"From the outside looking in, one can ask: Is this a money grab? One can ask: Is Formula 1, is Liberty Media kicking the can down the road for a different agreement, so that they can go from $200 million to $1 billion dollars extracted from Andretti-Cadillac?" he said. "Meanwhile, the commitment has been shown by Andretti-Cadillac, I think, to the tune of millions of dollars a month in preparing for the standards of complying with everything."

"We hope that we can resolve this to do business together for our mutual benefit, but particularly for America," he said. "But if not, we will have our questions answered. Because we have an obligation to protect the American consumer, to protect American companies, and that is our first allegiance. And those who are seeking to take advantage will be held accountable."

Representatives for F1 didn't immediately return an email seeking comment on the letter from the lawmakers.

"It's not just supporting Andretti. It's about supporting Americans," James said, adding that he has spoken to House Judiciary Committee Chair Jim Jordan, R-Ohio, who "seems very interested in learning more and asking" F1 questions about Andretti's bid and whether there are anti-competitive practices at play.

The press conference came just ahead of this weekend's Miami Grand Prix, as the sport returns to the U.S. for the first of three races in 2024. The other two are in Austin and Las Vegas later this year.

It also came on the same day that defending world champions Red Bull Racing announced that Chief Technical Officer Adrian Newey would leave the team next year. The move marks an earthquake for F1 as Newey is widely regarded as the greatest car designer in the sport. He has worked at Red Bull since 2006 and built all seven of its championship-winning cars — four with Sebastian Vettel and three with Max Verstappen, who is hoping for an eighth this year.

Andretti told NBC News he would be interested in hiring Newey.

"That's a simple question: 100% yes," he said with a smile.