In light of the new wave of liberal lawfare being waged against President Trump’s tariffs, it’s worth considering: do the liberals have a point? Rand Paul certainly thought so—recall that a few weeks ago he brought the Senate to a tiebreaking vote to halt the tariffs. This is because Article 1, Section 8, Clause 1 of the Constitution explicitly grants Congress the power to “lay and collect Taxes, Duties, Imposts and Excises” and to “regulate Commerce with foreign Nations”. Strictly speaking, Congress has these powers—not the Executive. However, Congress also has the authority to delegate powers to the Executive for...