If you’re looking forward to finding out who "won" the GOP debate just minutes or hours after it ends on Wednesday night, you'd probably be better off waiting a few days instead. It's not that there won't be plenty of immediate data to look at, from focus groups and instant polls to social media and web traffic. But as the past few months have shown, none of those are especially reliable guides. A focus group led by GOP pollster Frank Luntz after the first Republican debate in August suggested that voters had soured on Donald Trump -- a prediction not...