‘The Purge’ (R)

According to the what-if? scenario of The Purge, in the near future government will shut down for 12 hours one night each year — no police, no hospitals, no 911 — and people will be free to do whatever they want, even commit murder, without legal consequence.

The movie tries to explain its preposterous premise by claiming that the national crime rate has gone down to 1 percent, because most victims of the annual bloodbath are thieves and drug addicts and homeless people — you know, the kinds of people who want to steal your stuff and hurt you (white-collar criminals are apparently off-limits). Apparently, every bad guy in the country can be taken down over the course of one night, and mysteriously, without explanation, no replacements rise up until the following year.

James Sandin (Ethan Hawke) has become a wealthy man thanks to the purge, selling high-tech security systems that turn your home into an impenetrable fortress. While carnage reigns outside your front door, you can sip a fine Cabernet and spend quality time with friends, safe inside your luxurious mansion. The allegory is hard to miss, but writer-director James DeMonaco wants to have it both ways: He expects you to be horrified by the film’s central concept, but he also wants to stoke your bloodlust and root for the characters to get their hands bloody when an intruder sneaks into their house. Shoot! Kill! Chop him with that axe!

The Purge, which co-stars Game of Thrones’ Lena Headley as Hawke’s wife, is the kind of movie in which people are constantly running away into another room for no reason, forcing someone to go look for them. The film has some vague things to say about class and racial differences, but they are drowned out by the sounds of blasting shotguns and huge knives being plunged into people’s chests. The baddies carrying out their siege on the heroes’ home wear creepy masks and tend to pop up in unexpected places, which brings to mind 2008’s The Strangers, another home-invasion thriller that was far scarier, less self-important and had the courage of its convictions. The Purge isn’t just stupid; it’s also pretentious and often makes no sense. OK, so murder is legal for the next 12 hours. But do you really think your girlfriend is going to run off with you and live happily ever after if you shoot her disapproving father in the head?