The Trump administration’s section 232 review of the automotive industry may prove to be a race between the Commerce Department’s investigation and the Senate’s attempts to limit the President’s trade policy powers. Public hearings in the national security review are scheduled for July 19. Sen. Portman (R-Ohio) may introduce legislation to apply a stricter definition of “national security” and shift responsibility for that decision to the Department of Defense.

One challenge to the national security definition in the recent steel and aluminum review was that traditional allies inc...