The regrettable legacy of 9/11 and its ambiguous aftermath is the intrusion of the courts into the national-security realm. Judges, whom we insulate from politics, have no constitutional responsibility for national defense. It is supposed to be left to the elected officials accountable to the people whose lives are at stake.

There is wisdom in making national-security decisions political rather than legal. The law strives for rigorous logic, a one-size-fits-all balancing of public-safety concerns against individual rights. Over time, judges reliably expand both the ambit of these rights and the categories of entitled individuals — to include even non-Americans who bear no responsibilities of citizenship, and even enemies who make war on Americans.

Politics, by contrast, strives for social cohesion through compromise. It is not bound by logic but by public perception — in security matters, the perception of a threat’s severity and of the reasonableness of responsive measures. Security measures should be ratcheted up in a time of high alert, particularly in wartime; but they should ebb as our sense of vulnerability wanes, as priorities other than our protection seem more urgent.

Right now, we are in the ebbing phase. For nearly two decades, we’ve longed for that. But is it here because it’s time, or because we long for it?