I know at least one person who, around the time of the Iraq war, mostly stopped working and no longer pays taxes. It can be done, but it's a pretty serious lifestyle choice.

While there's a lot to criticize about US foreign policy, invading a western nation with a democratically elected government isn't on the list. You really can't sympathize with Saddam Hussein or the Taliban. I wouldn't (and didn't) stop paying taxes over it.

If the US government invaded Mexico or Canada, I might.