Today it's Barack Obama, demanding a "Buffett rule" and decrying the harm caused when "the gap between those at the very, very top and everybody else keeps growing wider and wider and wider and wider." Not so long ago it was John Edwards, intent on riding his "Two Americas" stump speech ("One America does the work while another America reaps the reward") all the way to the White House. Earlier still it was FDR, lambasting the wealthy who "did not want to pay a fair share" and boasting that he'd "increased still further the taxes paid by individuals in the highest brackets" because that was "the American thing to do."
Indeed, presidential candidates have been picking at the income-inequality scab since at least 1840. That was the year William Henry Harrison, running against incumbent Martin Van Buren during a recession, accused the president of pursuing policies "directed to the purpose of making the rich richer and the poor poorer." (Harrison won, but died a month after taking office.)
Those who peddle class resentment can always find ready takers; otherwise politicians wouldn't keep selling the same rug. But the demand for it is never as great as the demagogues imagine. Most Americans don't hate the rich, or even the very rich, and they don't despise the economic system that makes great wealth possible. "That all men are created equal" goes to the core of our national creed; its undeniable moral force led Americans to fight a horrific Civil War over slavery in the 19th century, and to embrace the legal and social upheaval of the Civil Rights movement in the 20th.