I’m not too worried. I’ve got my PipBoy (well, a PDA is close enough), a pistol, several bottlecaps, and a sharp knife to skin geckos with. All I need to do is get my hands on a Gauss rifle & I’ll be all set. I’m not wearing a jumpsuit though.
You’re talking about an event that would kill millions, destroy large parts of the agricultural heartland of the US, do untold damage to transportation networks and communications networks, disrupt air and ground travel from coast to coast, and would take trillions upon trillions of dollars to repair the damage from, not to mention gutting an entire population of farmers and ranchers in some of the most productive agricultural areas of the US.
I would think it would impact quite considerably on America being a world leader. I would think we would need about 20 years to lick our wounds and repair the damage before we would be anything like what we are now.
And of course, would depress the world agricultural production for years (though the addition of ash might actually enhance the soil once it all gets out of the atmosphere).
I’d suggest moving to New Zealand, except that under the vicinity of Lake Taupo is another supervolcano waiting to happen, though not as big as Yellowstone. Since it was only a few tens-of-thousands of years ago when that erupted, perhaps it would be safe for a while.
All kidding aside, humans in general have a hard time planning for rare events that cause large amounts of damage.
According to some studies done recently, a proper meteor detection system should save something like $100,000 for every $1 spent but because the event is so improbably small, nothing is being done about it.
I need to get one thing straight: We’re talking about a huge natural disaster that would leave hundreds of thousands dead, enormous damage to the infrastructure and economy, years of privation and so on, and your major concern is whether the US of A would still be calling the shots in global politics? Why?