"Without a National Defense some of your concerns will go away, but you'll also have a new set of problems. And I'm not entirely convinced that the new problems won't be worse than the old ones."
The "new problems" are the problems that were there before the old "solutions" were enacted, and are still there today. Which "new problems" did you think would suddenly crop up? Weak national defense? Americans complaining about harassment and unfair trading practices abroad? How would that be different from today?
The differences would be the complaints be about real things rather than imagined.