With a world on edge after the coordinated terror attacks in Paris, and as criticism grows louder of the Obama administration’s handling of adversaries such as Iran and Syria, tough talk and defiance have become strong currencies in the presidential race. Retired neurosurgeon Ben Carson’s mild-mannered, soft-spoken demeanor – which helped endear him to many voters in the first place – now appears to be working against him, while Sen. Ted Cruz’s tell-it-like-it-is, in-your-face style is now raising his stock. In the crucial state of Iowa, which holds closely-watched caucuses, the event in Paris on Nov. 13 changed many conservatives’...