Fully Qualified 1815
You definitely need a MIL issued CAC, Navy in this case. It's what provides quick visual verification of your MIL status, contains your MIL associated email/ID certificates.What if I have a civilian CAC?
Here's a pro-tip. Decide up front which CAC is more important to you, i.e. gets you paid. Modify the *other* one. Dual persona users have the hardest time because having two CACs will effectively turn them both off until one is PIV-enabled. Every time you update your certs or get a new CAC, you'll have to remember to have RAPIDS re-configure your CAC, or deal with doing it yourself through java web-apps, that barely work.