Going to put my money on the FDA. Couple reasons. The design of the phase 3 in Mexico is a tell. It’s the quickest way to approval and mass distribution and the country is desperate for therapeutic options. Goes without saying, the FDA is well aware. So...
Beyond the therapeutics and meeting the acceptable minimum standards for approval, this is about publicity and control. The FDA will fast track this very soon (especially with continued failures of other therapies) to bask in the headlines that the US has developed and approved a major breakthrough therapy. It’ll also keep the distribution under the thumb of the FDA regardless of if/when another country approves it.
Time will tell...but I do think this happens quickly