Greg Mankiw generally seems like a pretty open-minded economist, willing to consider viewpoints from across the political spectrum. But he does seem to make missteps when he decides to wage class warfare. For instance, his snide post “Even leftists believe in property rights” was more high school bully than Harvard professor. More recently, he happily posted evidence of a study showing that, in the past three or four years, the incomes of the rich have fallen (in terms of percentage) more than the incomes of the 99 percent.

“The rich get poorer,” Mankiw lamented, asserting that the study is proof that “high-income households have riskier than average incomes.”

Matt Levine’s Dealbreaker blog takes an ax to this argument, demonstrating that the wealthy’s income drop in recent years has to do with the shift to…

…a shareholder-value-driven economy where the working rich managed their firms for quarterly earnings target (and were paid with options and incentive comp) and the idle rich invested in hedge funds…

In other words, the system has been gamed so that when the stock market rises, the wealthy do immensely well, but when it plummets, they are disproportionately hit (though, don’t worry, they’re still doing better than everyone else).

And, of course, there are safety nets for the uber-wealthy: One, the money they’ve already made. And two, enormous golden parachutes wholly disconnected from their job performance.