I sat and read through the President's general order and the negativity that came after that. There are in my mind....two essential areas....which fell apart when the Pentagon sat and tried to envision this working.
1. Boot-camp. If you had transgender 'Joe' show up for boot-camp (female to male)....how would you handle the shower situation? Or 'Missy' showing up (male to female)? No one could ever detail the whole thing out. Would you force 'Joe' to the men's physical standards, and if you did....how many would fail. Few people realize this angle, but there's two different rule-sets for push-ups, sit-ups, and the 'run'. Which do you use for the transgender? Or do you make up a whole third-set of physical standards? No one ever said this part of the solution. My guess is that it became more difficult to solve.
2. Role of military in transgender health-care. No one could ever say that the military would not get stuck with the bill for hormones or surgery necessary. The hormone therapy? Someone has to pay, and if you were on some process and your remote medical unit couldn't readily provide the hormone on a regular basis....your success rate would go down quickly.
Oddly, there are a thousand categories in which you could end up being disqualified for military service. Epilepsy, low IQ, being too short, mentally unstable, etc. Early on in my career, I noted the episode that developed at the health clinic on base where they wrote an evaluation up on a records clerk, ensuring that she could not re-enlist. The reason? Continued incompetence. Week after week, she screwed up records and paperwork. After twelve months of dealing with her....it came down to the point of every single detail of what she did on a daily basis....had to be peer-reviewed and checked. As she was wrapping up the two-year tour (having roughly one year left on the contract), she was desperately trying to have the evaluation removed, and they were very firm in saying that the service just wasn't a place for her. They didn't want to 'fire' her or toss her out, but simply to ease her out at the end of four years.
Will this simply end with the transgender deal? No. I would expect the House and Senate to pick this up and write some forty-page law to just do it. Which physical standards will they use? It won't even be mentioned and the Pentagon will sit there and have to figure out the way of solving this mess.