Commentary Back in early 2016, when Larry Kudlow and I suggested that then-presidential candidate Donald Trump propose a 20 percent business tax rate for U.S. companies (down from the highest in the world rate of 35 percent), he enthusiastically endorsed this “America First” policy—not because he loved corporate America but because he realized that as long as small and large American companies were paying the highest tax rates, jobs and factories would continue to move offshore. We argued that the biggest beneficiaries would be American workers who would have access to more jobs and higher wages. The liberal economists we debated on this disparaged the tax reform as “tax cuts for big corporations and the rich.” They predicted that it wouldn’t work. In 2017, the tax cuts passed without a single Democratic vote. Now we would have a real-life scientific experiment on supply-side economics. Do lower tax rates generate more …