1) Japan and Europe for example have national debts usually ranging from 70 to 180% of GDP. The US is still at the bottom of that range.
2) Europe and Japan are facing aging populations and increasing costs to support that older population. We do too, but we have fewer social programs to fund. In addition their birth rates are too low to truly provide relief from snowballing debt (fewer younger people to pay for the older generation = more debt). In the US our birth rate is still healthy enough to provide population growth (more younger people to pay for the older generation). Furthermore, many European countries are facing shrinking populations which will be disastrous for their economies. The US is probably one of the developed countries better positioned to handle the baby boomer crisis.
3) Like it or not, taxes in the US are VERY low compared to most developed countries. Therefore we are better prepared than most to face this crisis. While we could raise taxes here to help lower the national debt, Europe has already pretty much maxed out its taxing power (I don't know about the tax situation in Japan).
4) America's economy has a lot of built-in flexibility (flexible labor market, population mobility, entrepreneurship incentives, low unionization rate, etc...) which will allow us to adapt and find new ways to grow.
So you can run, but you better do some research before deciding where to hide.
.
