Democrats have given up on taxing millionaires to finance payroll tax cuts, but just for the moment. President Obama is clearly zeroing in on "the 1 percent." With economic inequality at record levels, there's growing pressure for the wealthy to pay more for government programs. But how much more? It's no longer true that the rich necessarily get richer. What was the most stable segment of the economy now feels booms and busts more than anyone else. Nobody's sympathizing with people who've lost their yachts and mansions, but what happens to government if it has to depend on them?