This may yet be the most difficult challenge yet for Andretti; although it has proven to the FIA that it has merit on sporting, technical, and financial grounds, thrashing out a deal with FOM will be tough given that the existing 10 teams will put the championship under pressure.

After all, the existing teams have their own vested interests, and have been conspicuously cool to the prospect of any new entrants under the current anti-dilution fee set out by the Concorde Agreement.

This is set at $200 million, a fee that a new team must pay in full to be admitted to the grid. This is then separated out between the existing teams, who receive $20m of that each. This fee is effectively a way of subsidising any potential losses to income through prize money, TV rights, and sponsorship that an 11th team may create.

Owing to the championship's growing popularity, the existing teams have been steadfast in their belief that the anti-dilution fee should be raised to circa $600m given the expanding value of each team.

Naturally, the existing teams operate within their own interests and any support of an 11th team would be anathema to them. To paraphrase the more open reactions from current team principals, some teams would be accepting of an additional entrant if it sufficiently "grows the pie"; that Andretti's inclusion adds to the overall F1 pot rather than chip away at other teams' sponsors.

To others, they believe that the only way to preserve F1's current equilibrium is for a new entrant to buy an existing team - and if an existing team isn't willing to sell, then that's simply hard luck. There have been more outrageous claims in opposition; one suggestion was that F1 simply couldn't fit another team into its current infrastructure and that there wasn't enough space in the paddock - all while a film crew acting as an 11th F1 team occupies an extra garage slot...

Andretti has already tried the purchase-a-team route, and was a hare's breadth from agreeing a deal to purchase Sauber in 2021 - but could not agree how much control the current shareholders would retain.

In the past the FIA and FOM were united on the admission of a new team, but there has been an evident divergence between the two parties' approach to this year's tender process.

FIA president Mohammed Ben Sulayem was particularly keen on adding a further team to the F1 circus; the championship has not run with 11 teams since 2016, when Haas joined the grid and Manor had been given a short reprieve from financial oblivion.

Thus, the FIA had agreed to open a tender for prospective F1 entrants for both 2025 or 2026, which would offer some degree of latitude to a team looking to make a success of its emergence on the grid. After all, the 2026 season is set to include widescale changes to the powertrains, and there yet be a glut of aerodynamic changes too.

But FOM has taken a more cautious approach under the leadership of Stefano Domenicali, who has maintained the need for a team to add value to the championship. This has been echoed by most of the F1 teams.

Andretti, despite having been given the FIA's green light, still has work to do to convince FOM that it can bring something to F1. It already has a number of factors onside that make it a tantalising prospect, but F1's stakeholders may feel that the team is merely paying lip service to its own criteria.

One such criterion is that FOM hoped to use its 2026 regulations to attract more OEMs to F1. The current turbo-hybrid regulations only tempted Honda on board; 2026's revised hybrid rules have since tempted Audi to come in as a full manufacturer team, while Ford has put its name to Red Bull's powertrain project for the new regulations.

Andretti has attracted its own major label, albeit not strictly as a supplier; GM has elected to throw its support behind the project with its Cadillac brand, which beyond its range of luxury sedans has carved out a reputation in motorsport with its endurance racing efforts. Expanding to F1 only furthers the distinctly American flavour of the team, which the team hopes would make it an asset in continuing the championship's growth in the US.

This is something that Haas has not been particularly keen on capitalising on, and any references to its US ownership have been muted at best. It is effectively an Anglo-Italian outfit, with the Stars and Stripes barely featuring. Ferrari boss Frederic Vasseur stated in his opposition to choosing a team based on nationality that F1 already has an American team - but does Haas's approach to that particularly chime with an American fanbase? Perhaps through its name-brand recognition with the Stewart-Haas Racing NASCAR team, it has some influence, but it has nowhere near the draw of the Andretti name in US racing circles.

It is to Andretti's credit that it has managed to secure the pull of GM, even if not as a thoroughbred manufacturer entity as there isn't likely to be a Cadillac powertrain for the foreseeable future. But, one could make the case that Ford is simply helping fund the Red Bull Powertrains operation for 2026, rather than taking ownership itself...

F1 should see value in the Andretti Cadillac dyad in name alone, especially as the US commands three races on the current calendar and Andretti's emergence may well be a selling point. But there's more than a name; the FIA has clearly seen value in its technical project too. Featuring a range of veteran F1 engineers such as Nick Chester and John McQuilliam, Andretti has the technical know-how to ensure it gets up to speed. It has invested in its facilities in the US to accommodate the design and build of an F1 car, with certain activities to be based in the UK.

The suggestion is that Andretti will carry backing from its IndyCar sponsor Gainbridge, part of financial services giant Group 1001; if this comes to pass, it already shows the pulling power that Andretti could possess in the US sponsorship market.

Will that be enough to prove that the team will "add value" to F1, as is Domenicali's desire?

Andretti will ultimately have to show its financial figures, value of the brands it has already accrued in support, and hope that F1 is sufficiently enthused. But this depends on how FOM will handle the process of admitting the team to the championship under the current Concorde Agreement - which notably expires at the end of 2025. Under this agreement, Andretti can still lay claim to a team under the $200m anti-dilution fee; for 2026 and beyond, the teams will likely ratchet that cost up to an eye-watering sum before putting pen to paper.

Pressure from the existing teams could make things difficult, and influence F1's starting position in its negotiations with Andretti. It will be anything but straightforward, and the two parties could theoretically be locked in a stalemate for months. If there's a resolution in a matter of weeks that ends with Andretti fully admitted to the 2025 grid, it would arguably become the largest shock in F1 since Nico Rosberg dropped his retirement announcement five days after winning the title. Perhaps even bigger, given recent discourse.

It will be tough for Andretti. FOM has also put itself in a position where, if it does not relent, it appears to be in the pocket of the existing teams - some of whom have questionable value themselves in their current guises.

Andretti could come all this way and fall at the final hurdle. But that likely would not be of the team's own making - pressure for F1 to move previously agreed goalposts may be the determining factor. If there are legitimate grievances about Andretti's project, then the FIA would likely have found them by now through its own process - and if the team is denied for nebulous and arcane reasons by FOM, then this opens up the prospect of litigation - which would be an ugly end to previously salubrious circumstances.