Starting around 1980, a third American oligarchy emerged. Since then, the median wage of the bottom 90 percent has stagnated. The share of the nation’s wealth owned by the richest 400 Americans has quadrupled (from less than 1 percent to 3.5 percent) while the share owned by the entire bottom half of America has dropped to 1.3 percent, according to an analysis by my Berkeley colleagues Emmanuel Saez and Gabriel Zucman. The richest 1 percent of Americans now has more wealth than the bottom 90 percent combined. The only other country with similarly high levels of wealth concentration is Russia