Realistically, however, foreign income gets a pretty high exemption, and places like Canada also enjoy a tax reciprocity agreement with the US. What does this mean? 

If I were working in Canada right now, I would have to earn 124 thousand CAD before I have to worry about paying US taxes. This is in addition to my US personal exemption and all the other tax accounting tricks I have to deal with. With my wife in the mix, that becomes 248k CAD, and that number goes up every year indexed to inflation. That's income that the US will not count as income at all for me. If I get lucky enough to earn, say, 258kCAD (210kUSD at current exchange rates), then I'll subtract the 202k USD exemption from the 210k USD income and then pay an awesomely amazing...$800 in US taxes, assuming Canada's tax reciprocity agreement with the US doesn't eat those away. Make no mistake. Living in Canada means I'll pay less US taxes than if I stayed here. But I still get to vote! That was my point. :3