Tricare doesn't cover CPMs and you threatening to do a UP or UC isn't going to convince the rep you talk to on the phone, who has no control over Tricare policy anyway, to change it. No one you will talk to can change that policy, actually. The entire Tricare rule about who can be covered would have to change for that to happen, and there's no
one person who can do it. Right now, Tricare only covers authorized providers. That's why chiropractors aren't covered, naturopaths aren't covered and CPMs aren't covered. None of those types of providers can be authorized providers.
I really wouldn't "threaten" to have an unassisted pregnancy, because it isn't going to help and it's just going to make you look like one of those people who thinks she can get her way by acting obnoxious to the "little guys" who have no control over those sorts of things. (Sorry, but it's true.

) Besides, it's no "threat" to them and will
really make you look bad, because a person who does a UP or UC because she's educated and really believes this is best for her is completely different from someone doing it because she thinks it will prove a point. The second makes you look like you'd risk your baby's life or health just to have your way - not the most convincing way to change a government policy. After all, if you really wanted and believed in going UA, you wouldn't be arguing with them about covering a CPM. Do whatever you want, but this is guaranteed not to work and it isn't going to leave anyone with a good impression of you and will likely piss them off.
I know it really sucks, but most CNMs don't do home births anyway. The CNM I had for my first daughter's birth did not and never had done home births. And you're right in assuming that the MTF CNMs don't do home births - the only births they attend are there. There has been a campaign to change Tricare policy going on for over 5 years now. Maybe someday they'll change it, maybe not. Even if they do, many midwives just can't accept the amount Tricare pays, so you could still pay a significant out of pocket cost to cover some of the difference. There have been some people who have gotten coverage for CPMs by accident. Basically, they submit their claims and someone at Tricare doesn't realize it's a CPM instead of a CNM, so they approve it. That always happens after the fact, though. You can't get a referral to a CPM on Prime. The best you can do is see her and hope Tricare will accidentally cover her out of network or reimburse you on an out of network basis. Most people are not successful with that, but some are because the reps just don't always notice.
As a side note, having had two unmedicated, uncomplicated deliveries, one for which the midwife made it to my house just in time to catch the baby, I would still say that birth is not "inherently safe". It is "usually safe" but safety is not an intrinsic part of birth. Safety is not a guaranteed aspect of delivering a child, which is why women who do have a planned UC take care to educate themselves on exactly what symptoms or signs would indicate that they need to transfer to a hospital. They are aware that, while birth is
usually safe and uncomplicated, there is always the possibility of danger to either the mother or the child. I think it's important to be aware of that, because safety definitely is not
inherent to the birth process. Any mother who has lost a child during an unmedicated, uncomplicated, un-screwed-with delivery can tell you birth isn't inherently safe, but rather just that it's usually safe.