I think people are massively underestimating the FTC's chances on a preliminary injunction, which I view as roughly a coin toss of giving the FTC a result it likes.

Immediacy of harm in merger cases is usually pretty easy. The FTC just cites recent news articles indicating that Microsoft is looking for ways to close without CMA's approval, and prior Microsoft statements that Microsoft intends to close without FTC approval. Then it states that unwinding a merger is more difficult than stopping one, and that divestiture often fails to produce as good a competitor as existed pre-merger. That language shows up tome and again. Microsoft could almost certainly win the Preliminary Injunction case by agreeing that it won't close until X date or until Y thing occurs, but I'd put that result in the "result FTC likes" column.

The other big question is if the FTC case against the merger presents a genuine issue of material fact to be determined by the ALJ. If such an issue exists, the U.S. District court generally does not want to displace the ALJ as the initial fact-finder.

The result Microsoft is hoping for is: "There is no genuine issue of material fact, and Microsoft is entitled to close the merger as a matter of law." This, if not disturbed by appeal, would essentially render the FTC's internal trial pointless, because any successful block internally would be successfully appealed by Microsoft.

The FTC is hoping for the result: "A genuine issue of material fact exists to be resolved by the ALJ, and Microsoft's public comments create a real possibility that, without an injunction, they will close the deal, so we are granting the injunction." This way, if the ALJ rules for the FTC, then FTC is strengthened on further appeal because there was already found to have been a real factual issue for the ALJ to decide. That doesn't foreclose Microsoft winning, but it adds to FTC ammo.

That having been said here, I think Microsoft is playing chess and FTC is playing "tic tac toe my god is that a flying squirrel?" I don't think Microsoft plans to close over/around the CMA. I think they made noise about it and FTC took the bait. I think this gives Microsoft a real shot at the ruling they want, and if they get it, the CMA is left standing alone, and Microsoft's arguments to the CAT on irrationality, failure to adequately consider comity, etc. are strengthened.

If Microsoft gets its best ruling, it is helped more than the FTC is helped by its best ruling, so the rope-a-dope was a reasonable play.