I goog'd 'US Demographic Trends 2050' and Pew Research puts the US population at 438 million by 2050, mostly due to immigration and the children of those immigrants. The population chart that HHH2O posted has the US with the highest birth rate in the Western world besides the anomalous Ireland. I think that the US is literally going to grow its way out of its debt in a way that Greece cannot so I'm not over wrought by the the current US debt hand wringing. I think it's over blown.