I noticed they are in caps and have periods between the letters; meaning they must stand for something.

I Googled for it and searched the in game info and could not find it. Perhaps the game creators never assigned the acronyms but, if they indeed do stand for something i would love to know out of curiosity.

This is NOT what the acronyms actually are, but, i wanted to venture a guess before i find out what they really are.

P.A.T.R.I.O.T

pan
american
tactical
response
intelligence
operations
team


S.M.A.S.H

special
military
alliance
southern
hemisphere


S.A.B.R.E

sovereign
alliance
British
reconnaissance
entity


H.A.M.M.E.R

hussar
agents
Marxist
managed
exceptional
ranks


A.N.V.I.L

Asian
nations
vital
intelligence
leadership

As far as I am aware, having played the game since 2005, they don't mean anything. Just a play on an old spy trope, á la Man from UNCLE.

I haven't played for many years now, but I always thought they were capitalized code names and not acronyms (although they may appear as acronyms in the game?).

Kind of like CONTROL and CHAOS (from Get Smart).