you can have the most powerful army in the world and lose, been proven time and time again

last set of war games run in the mideast theatre that I read about ended up that way

tactics and strategy mean just as much if not more as the hardware and equipment and men

for being the world's military super power the US sure does make an awful lot of really stupid tactical and strategic errors, and it's had its nose bloodied for it too at the cost of perfectly good soldiers and equipment, Iraq and Afghanistan among others are textbook examples of what NOT to do

more to it than just military though, you have to have the economy and finances to support it, let those fall apart and your military becomes useless, just like bad strategy and tactics can hand you a defeat very very quickly