Moments like this are not uncommon in presidential elections, and when they come, they tend to matter. For unlike the posturing and platitudes that constitute the bulk of what occurs on the campaign trail, big external events provide voters with something authentic and valuable: a real-time test of the temperament, character, and instincts of the men who would be commander-in-chief. And when it comes to the past week, the divergence between the resulting report cards could hardly be more stark.