The Senate did its job.Former congressman Matt Gaetz (R-Florida) will not become attorney general, withdrawing from consideration this week after he spent a day on Capitol Hill learning that at least four Republicans would oppose his nomination — enough to tank it on the Senate floor.On the most basic level, this shows that President-elect Donald Trump feels constrained by the constitutional order. It also suggests that enough Republicans will refuse to let him make “recess appointments” — a maneuver of questionable constitutionality that would have allowed Mr. Trump to install high executive branch officers without Senate consent, at least in...