With whispers that former New York City mayor and billionaire Michael Bloomberg may mull a run for the White House, politicos are already hyperventilating about how he would shake up the current field. Would he run as a Democrat, a Republican or an independent (he's been all three)? Would he take on billionaire rival Donald Trump? Would he swing at Hillary Clinton (whom he reportedly does not like)? Yet despite the excitement from election-watchers, Bloomberg's entry is unlikely and ill-advised anyway. In an interview with Byron York, Republican strategist Alex Castellanos summed it up: "Michael Bloomberg is a solution in...