Fifa president Gianni Infantino has been dragged into the debate over introducing promotion and relegation to football in the USA.

Infantino was presented with a letter this weekend calling for FIFA to bring the US into line with the rest of the football world, by enforcing its Article 9 on the US Soccer Federation.

This represents the latest exertion of pressure on the USSF to introduce an “open system” in American football. The USSF is currently facing multiple legal challenges, including one at the Court of Arbitration for Sport, from football clubs hoping to open up the current closed hierarchy in the sport in the US.

This letter was written to USSF president Carlos Cordeiro, signed by hundreds of football clubs across the US who are hoping for reform.

The letter blames the unhealthy state of football in the US on the league structure, which has Major League Soccer perched at the top, accessible only to those who buy their way in: “The failure rate of clubs and leagues across the US soccer landscape vastly exceeds any other country in the world,” the letter says.

“Dozens of team owners from multiple leagues have seen their investments go to waste and hundreds if not thousands of players have seen their potential unrealised. In global soccer terms this situation is unique and, the evidence suggests, is a function of the exceptional nature of our closed model.”

Clubs and leagues across the US have continued to sign the letter over the weekend to register their opposition to the “closed model” of the USSF. “More than 20 new clubs have signed on to the letter in the last 48 hours and we expect that number to continue to rise,” organiser Daniel Workman told The Independent.

“It has been a grassroots effort and we’ve seen support come from different areas and levels of the country. The interest level is high in the grassroots, but the Federation have shown little interest in organising a pyramid.”

This letter follows the launch last year of a high-profile legal challenge to the USSF’s closed system, also brought by two clubs from outside MLS.

Kingston Stockade play in the National Premier Soccer League (NPSL), effectively the fourth tier in the US, and were set up by FourSquare founder Dennis Crowley.

Miami FC play in NASL and are owned by Riccardo Silva, the Italian investor who set up sports rights company MP & Silva with Leeds United chairman Andrea Radrizzani.

Between them, Kingston Stockade and Miami FC brought a case to CAS, calling on FIFA to impose their own Article 9 on American football. Something they have been clearly unwilling to do in the past.

This weekend’s letter has broadly the same goal as the CAS case, to push FIFA into pressuring USSF to open up the American game.

“Ultimately, you can’t ask the USSF politely to do this,” Crowley told The Independent last year about the CAS case. “They’re not interested. What we’re trying to do with the CAS filing is to say ‘listen, USSF has to play by Fifa’s rules.’

People have been trying to do this for years, and USSF has not been forced to respond. The thinking is that the CAS filing forces the issue, forces them to articulate their position, and hopefully forces them to make some changes here. The USSF has to acknowledge that this is part of Fifa’s rules.”