Trump’s actions on pandemic relief aren’t illegal. They’re just ineffective.

Within hours of President Trump’s announcement Saturday that his administration would provide pandemic-related relief to millions of Americans, lawmakers on both sides of the aisle assailed the move as yet another instance of presidential overreach. House Speaker Nancy Pelosi (D-Calif.) and Sen. Ben Sasse (R-Neb.) — who don’t agree on much — settled on the same phrase to describe the president’s actions: “unconstitutional slop.”

That’s understandable — but wrong. Trump has so often exceeded normal limits on presidential authority that it is easy to assume unlawfulness on his part. But...