We could have dealt with that without invading Europe.
Im not saying we should not have invaded Europe, we had to. However, that is not he same as saying Germany would have taken us over.
If hitler had been allowed to crush USSR and England (which would have certainly happened without US intervention), we would have had UK and French 16-year olds coming over the CAN and MEX borders with rifles by 1947 or 1948.
he would have used the resources of the vanquished, and we would have eventually lost, as the other great superpowers did.
If Hitler owned that side of the world, trade to us would have dried up via a nice nazi embargo. it would have meant a slow starve as we were blindsided by invaders. Plus with the advent of the WMD at that time.... heck, hitler would have been launching Firebomb attacks from MEX and CAN. His men probably would have had the nuke by 1946 as well...
You have to attack the bully while he's busy fighting 3 other guys, or after he whoops their asses it'll be the bully + 3 enslaved fighters coming at you... shitty odds