Terrorists are weak actors who use violence to induce overreaction on the part of their stronger victims. That lesson was on display today when someone overhearing radio traffic from a routine Potomac River Coast Guard exercise misinterpreted it and alerted the media. Among the results was a 20-minute grounding of planes at Reagan Airport.

The good news is that the country is relatively safe. Americans and the national security establishment are tuned to the threat of terrorism. No attack to rival 9/11 ever occurred, and it’s unlikely that one ever will.

But the 9/11 attacks had a dastardly effect. To match the results of those attacks, we imagined that terrorists had outsized technical skills, support networks, and insights. Vigilance and continued antiterror efforts will ensure that they never do.

The bad news is that the government has never issued any reassuring signals. American society remains on edge and predisposed to overreact when something happens and — in this case — when nothing happened. The “scare” produced by the Coast Guard exercise illustrates how sensitive the country remains to terror fears.

Despite improved rhetoric and the promise of sensible, strategic counterterrorism, the Obama administration has yet to give the country confidence in its security. It has not articulated its counterterrorism plan and it has not created or implemented a terrorism communications plan. Unlike health care and education, these are responsibilities of the federal chief executive.

Without a strategy and communications plan in place, the administration will be at a loss to keep the nation on an even keel if and when any real terror incident occurs. The Obama administration must plan, and must be seen as having planned, if it is to prevent any future terrorism event from needlessly harming the country with panicky overreaction.

Based on what I’ve read, I see no fault in what the Coast Guard did, and I hope their review of the incident produces no changes in their procedures other than perhaps better preparation to quell overreaction.