sure we can
we probably shouldn't
and it would definitely not be a good idea
but we could
If we can't steamroll a bunch of Afghanistan hill-men with AK-47's and RPG's, I doubt we could steamroll a major power.
Who's to say these "Major powers" won't use the exact same tactics on us. We've adapted to this kind of warfare to counter it in a decent manner, but "decent" is simply not enough.
Sure we could steamroll a large standing army, but any smart commander will not face a technologically advanced army head on.