Commentary Traditional supply-side policies stimulated U.S. growth to such an extent that by 1906 U.S. workers became the richest workers in the world, a trend that continues to this day. Last week, Treasury Secretary Janet Yellen proposed relabeling President Biden’s Build Back Better policies as “modern supply-side economics.” Yellen says, “Modern supply side economics seeks to spur economic growth by both boosting labor supply and raising productivity, while reducing inequality and environmental damage.” Yellen wrongly claims Biden’s modern supply-side strategy is superior to traditional supply-side economics, which stresses limited government spending, cuts in regulatory burdens, and lower tax rates. According to Yellen, traditional supply-side policies have failed to produce their promised benefits. Let’s examine the history of traditional supply-side economics and consider the extent to which it “failed to produce its promised benefits.” Then, let’s look at the history of the Biden administration’s “progressive” policies, which Yellen has relabeled “modern …