From the spooky noise that accompanies the very first shot—I think it's supposed to be an air raid signal, but for a moment it sounds like a Morricone score—it's clear that A Day Called "X" isn't your average 1950s civil defense film. Shot with a cast of non-actors, including the city's real mayor, it imagines Soviet airplanes approaching Portland, Oregon; for 27 minutes, we watch as the citizens evacuate and the municipal government retreats to a blast-proof bunker.
There is no Strangelove-style chaos here: All of the officials do exactly what they're supposed to do, as does virtually everyone else. The government is supercompetent, the citizens are generally compliant, and the handful of stragglers don't cause trouble for anyone else. But if the program, which aired on CBS in 1957, doesn't give us the conflict and micro-crises we'd expect from a Hollywood movie, its vivid documentary style keeps it from getting dull. (In some scenes, the producers felt the need to superimpose the words "AN ATTACK IS NOT TAKING PLACE" on the screen, presumably for fear that someone at home might mistake the show for the news.) And it's a pretty good time-capsule artifact too: a glimpse back at an era when the fear of a Soviet attack was high, when nuclear bombs would be delivered by planes, and when Portland could credibly be called an "average American city."
As the narrator (Glenn Ford!) mentions, Portland had done a practice evacuation two years earlier, in 1955. That was called Operation Green Light, and you can read an old newspaper account of it here. For past editions of the Friday A/V Club, go here.