protective wall

The easier an act is, the more readily, if it is deleterious, will popular sentiment build a protective wall around it.

I was surprised to find out that this city within its protective wall—the perimeter—is the only one on the planet.

Like living fingers they pierced that protective wall, flinging it back, until only the tall central pillar remained.

Even if the Red did possess a protective wall device, could it operate in full against a landslide?