Is USA at war with the rest of the world now?

I think Trump is a madman

How complex of an answer do you want? I typically flag posts like this for lacking curiosity and substance, as much as I abhor war.

In a broader context, the Cold War was already America's Mexican standoff with "the world" and they won by default. You live in a hegemony where America gets the first and final say in trade, warfare, nuclear deterrence, missile defense and surveillance. You don't have to get jingoist about it, but maintaining that hegemony is the goal and it will eventually end with a standoff against China, probably focused on the First island chain.

With that info, you should be able to generally extrapolate from [YOU ARE HERE] and "Invasion of Taipei" if you've got a loose understanding of geopolitics. If not, start here:

https://en.wikipedia.org/wiki/Monroe_Doctrine

https://en.wikipedia.org/wiki/Sphere_of_influence

No. Most countries are not. However, they have managed to get into tense situations with Russia, China, most of the Middle East, parts of Africa and Latin America.

Most of Europe and Canada are in a difficult situation with the USA right now.

when Ronald Reagan was president, 87% of Swedes said that USA is greatest threat to world peace.