The spectacular nature of the 9/11 attacks made both enmity and hazard appear enormous. Within a few years both appeared considerably less so, perhaps because the enemy’s capabilities were quickly degraded; perhaps because they were never that great to begin with, so that 9/11 was more or less a one-off; perhaps because the opening of a second front in Iraq signaled a diminished focus. Whatever the case, we were soon back to ordinary political squabbling.

As horrific as the Newtown massacre was, it was an act of madness, not war. If there was a “common enemy,” he had already died at his own hand. The massacre could not galvanize the nation as Pearl Harbor or 9/11 did. It could only galvanize already antagonistic domestic groups against each other: the gun-control nuts vs. the gun-rights advocates (or, as the former would have it, the gun-control advocates vs. the gun nuts).

There is comfort in watching politics with an ethologist’s detachment, in thinking of it as the playing out of biological instincts. Your adversaries don’t seem quite so menacing when you imagine them as herring gulls pulling up grass to make their point. Thinking of yourself that way is an antidote to self-seriousness. And the most comical gulls of all are the angry centrists–the Nolabelists, the Frums and the Avlons and the Cupps–who madly pull up grass to express their outrage about all the partisan grass-pulling going on.