President Trump’s tariff spree is, we gather, being met with a wave of regrets on Capitol Hill. The poor dears. The Framers, in their wisdom, delegated solely to Congress the authority to lay and collect tariffs.* Yet after the infamous Smoot-Hawley tariff of 1930, the solons let this power slip out of their hands. Congress passed a series of laws giving the president the ability to impose tariffs, largely at his discretion. Now some legislators want to reclaim their power. A bill pushed by Senator Grassley, Politico reports, would require the president “to notify Congress within 48 hours” of setting...