Maybe not shut down, but I imagine if the US did something truly bad (nuking an innocent country?), and there would be strong worldwide outrage to the point that everyone would boycott - or even riot - against American companies abroad, that would be pretty bad for US, and I assume/hope something they're not willing to risk.

That being said, the US is becoming quite a scary country, with how far it has expanded its military power all over the world, and the technological advancements (mass surveillance, drone attacks, future autonomous combat robots, etc), are only going to make this a bigger problem for the world.

The thing is it probably wouldn't be as scary, if everyone else could be assured that the US public has quite a good grip on its own government, and that we can expect them to act pretty rationally and reasonably. Unfortunately, that doesn't really seem to be the case, which amplifies the fear about US becoming too strong. For all we know we're just one president/government away from US starting to act truly evil (although many would say they are already doing that).