Get those USA slow units to the battle faster:
     Most  battles  need support eventually and if you need a slow but
powerful unit to get from your base to the battle on the other side of
the  map,  use  your  Chinooks.  A  single  Chinook  can carry up to 2
vehicles like the tomahawk missile, though some for some units you can
only fit one in a Chinook. But its a quick way to keep the fight going
and get that one unit were it needs to be to win.

US defense strategy:
     Build  four patriot missiles and two firebases (Artillery center)
inside  each  of  the  firebases put a sniper tw rockets and a machine
gunner  This  will  tear your enemies assault vehicles and infantry to
pieces very quickly.