Possibly. Although I live in a state that was once a part of a confederation. Things didn't quite work out, though.
Let the states govern themselves again. Federalization was a huge mistake. Federalization is the cause of the culture war. It is the cause of most of our national problems.
But what happened after the Convention? Rebellions everywhere as urban grifters and speculators, such as Hamilton, used federal power to dispossess the American people of property and rights. Shay's Rebellion and the Whiskey Rebellion come to mind. It's been a massive shit show ever since.
So what do you think things would have looked like in 1929 just under the Articles of Confederation? Or during WWII? Methinks it would not have been as great as you make it out to be.
I seem to recall the Greek confederation defeating the largest empire that ever existed on this Earth (up to that time), twice.
Going back to the world wars, the Anglo world was hardly united under one government and yet we all fought together same as ever. This was our downfall in a way, since we backed Great Britain in WW1 which, in hindsight, was a mistake, setting up our civilization for ruin.
Confederation is the natural extension of human bonds. We tend to defend those with close ties to us, even when we kind of hate them anyway. If somebody attacked California with a nuke, I'd still avenge those soy bastards.