Not literally balloons, but guided drones generally. They would make the US "more invadable" by being an invasion. Think about it being just a constant for years, and disrupting American society kind of like covid. People would have to change their lives, consider everything in relationship to defense, even if there were few casualties. It would be demoralizing if most of the existing weaponry was no use.
I haven't gone out of my way to familiarize myself with the perennial rocket launches at Israel, but that's the general sort of thing I'm picturing. Harassment that would demonstrate people are never safe, while not rising to the level where the international community would accept massive retaliation.
How are drone attacks an invasion? So from your own argument, do you consider Israel an occupied country because rockets are constantly launched at it? How about London during the Blitz? I don't think either group would ever consider themselves having been 'invaded'.
In both cases, the rockets weren't/aren't guided precisely and can't loiter, right?
And in any case, Israel is used to it and used to having missile defense, and is a very small country. Nobody expects that any part of the country is far away from the borders and enemies. Whereas it would be a sea change for the US, if attacks could occur anywhere, and psychologically it would be like an invasion.
I'm using "invasion" loosely to mean an attack that reaches inner areas that people take for granted are safe, not necessarily boots on the ground.
Sure, if you define 'any attack whatsoever' as 'invasion', then, of course -- according to your own definition -- any attack is an invasion. Just doesn't mean anything anymore.
I haven't gone out of my way to familiarize myself with the perennial rocket launches at Israel, but that's the general sort of thing I'm picturing. Harassment that would demonstrate people are never safe, while not rising to the level where the international community would accept massive retaliation.