Is a passport needed to travel to Mexico if I am an active duty marine?

Ive got a passport on the way, but it may not make it to me on time for my trip. I have read on a few sites that a certified birth certificate and a government issued ID will do, but I need to be totally sure. So my question is basically this: In the case that my passport doesnt get mailed to me on time, can I just take my certified birth certificate, military ID, driver's liscense, etc. and be let back into the country? Thanks in advance!

You need a passport if you are flying. You will need a passport for other types of crossings next year.

If you're driving then you'll be okay.

If you're flying then you need a passport.

according to my military knowledge
wear your dog tags. drivers lic. if it worked back in the 70's
for my brother from nam. why not for you.
of course wear the uniform....
best