The premise is about as plausible as Escape from New York. If crime can increase so much that Manhattan must be cordoned off as a separate, lawless prison, than the nation could establish a 12 hour period annually where its citizens can “purge” and commit any crime without punishment. The purge is a mix of a social reform (by allowing one night of consequence free crime, we have no other crime the rest of the year) and patriotic-religious act. But it occurs in 2020, and as bad as either Bush or Obama has been, I can’t see that kind of institution gaining traction so quickly. Frankly, it is unlikely the government could get the website for The Purge up and running in 6 years. In the end, the filmmakers don’t really invest much in the concept, and as my son remarked, “the problem with the movie is that you didn’t need The Purge to make it.” He’s right. When the killers looking to take advantage of their wild night surround the well fortified home of Ethan Hawke and his really stupid family (note to self; on Purge night, make sure your foolish son doesn’t get all Good Samaritan and lift the security gates), they may as we’ll be zombies or Manson family members or the bad guys in The Strangers or You’re Next. There is no reason to go high concept if you have no intention of exploring that concept.
Or maybe not. On a budget of $3 million, it made $64 million.