What we should be asking is how are we going to fight once the initial stages have finished and all the expensive weapons and equipment have been used or destroyed.
There is no way that replacement aircraft, ships, tanks etc. will be manufactured in quick time (like what happened in WW2). We no longer have the factories, infrastructure and skills to produce them in large numbers. Besides, it often takes several weeks just to get a washer...
Unless we can out-produce the opposition, we are likely to lose (especially as the likely candidates don't really care about their manpower).
Of course, that's for a conventional war. Once it goes the other way, all bets are off anyway.
If only we could be nice to each other...