In the third installment of the "Purge" series, the year is 2025 and a presidential candidate is running on the premise to do away with the night of terror forever. (  / Universal)

“The Purge: Election Year” is less tense than a political argument on Facebook, and about as much fun. Each sequel in the franchise is a reinvention: “The Purge: Anarchy” (2014) went beyond the 2013 home-invasion thriller to write a parable about class bitterness. “Election Year” turns its focus on hypocrisy, looking at how elites and insurgents jostle for power. Violent yet also cynical, this action film never develops a sense of danger.

In his third outing as writer-director, James DeMonaco explores a United States that solves its problems with an annual “Purge,” a 12-hour period during which all crime — including murder — is legal. This time, there is a popular U.S. senator, Charlie Roan (Elizabeth Mitchell), whose presidential campaign includes a promise to end the event. Her message inspires Leo Barnes (Frank Grillo), the hero of “Anarchy,” who volunteers as her head of security, while her political opponent (David Aaron Baker) conspires to murder her during this year’s Purge. Charlie and Leo survive the siege of her Capitol Hill rowhouse, taking shelter in a deli owned by Joe (Mykelti Williamson). Together the three fight off deranged teenagers, amoral Purge zealots and a neo-Nazi militia.

Elizabeth Mitchell stars as U.S. Senator Charlie Roan, who runs her presidential campaign under the promise that she’ll end the Purge. (Universal Studios)

(L to R): Mykelti Williamson as Joe Dixon, Frank Grillo as Leo Barnes, Joseph Julian Soria as Marcos, Betty Gabriel as Laney and Mitchell as Senator Roan in "The Purge: Election Year." (Michele K. Short/Universal Pictures)

Temporary lawlessness should inspire genuine despair, or at least a gleeful sense of mayhem. Instead, “Election Year” is a toothless affair, one where Grillo and the others are only going through the motions of survival. DeMonaco’s challenge here is that the Purge has become part of the fabric of American life; when the characters in the movie experience no sense of shock, neither do we.

There are few clever details in the production design, the sort of world-building that helps define a cinematic dystopia. What’s worse is the action itself. Even DeMonaco seems bored by the sieges, escapes and gun battles. Silly one-liners are the only saving grace, and that’s because such acting veterans as Williamson know how to sell them.

The villains in “Election Year” are monsters, or radicals who believe the ends justify the means. That points to one stupidly obvious message: The Purge is a bad idea. DeMonaco lacks the curiosity to explore how we got there, or what it means.

R. At area theaters. Contains bloody violence, terror and strong language. 110 minutes.