What will you do when terrorists attack, or U.S. friction with some foreign power turns into a military confrontation? I don’t mean in your personal life, where you should keep calm and carry on. I mean politically. Think about it carefully: The fate of the republic may depend on your answer.

Of course, nobody knows whether there will be a shocking, 9/11-type event, or what form it might take. But surely there’s a pretty good chance that sometime over the next few years something nasty will happen — a terrorist attack on a public place, an exchange of fire in the South China Sea, something. Then what?

After 9/11, the overwhelming public response was to rally around the commander in chief. Doubts about the legitimacy of a president who lost the popular vote and was installed by a bare majority on the Supreme Court were swept aside. Unquestioning support for the man in the White House was, many Americans believed, what patriotism demanded.