Don’t underestimate Rand Paul as a 2016 presidential contender

The first nine months of 2013 have convinced us of one thing: Rand Paul acts, and the rest of the potential 2016 Republican presidential field reacts.

On drones, the senator from Kentucky led a 13-hour filibuster that drew Sen. Marco Rubio (R-Fla.), among others, to the floor in support. On Syria, Paul was out front in his opposition to a military strike — a position that more than two dozen of his Republican Senate colleagues came to share.

Paul, in short, seems to be a step or two in front...