Here, director Ken Loach takes a stab at exploring the long-simmering tensions in Ireland that exploded in 1920, as guerilla columns fought against the British military forces that had been deployed to block the movement for Irish independence. The result of the violent struggle was a truce and a treaty — which only splintered the country into a state of civil war between those who were happy to see the feared “black and tan” squads leave and those who felt that the Irish deserved a more decisive break from the British government. Loach works with a screenplay by Paul Laverty that essentially compresses the passions of the struggle into the story of two brothers who fight together but end up taking opposite sides after the treaty is signed. Though the brother-versus-brother clichés are pretty hoary, Loach has a no-nonsense approach to this style of filmmaking, and though the film is perhaps overlong and a mite formulaic, it’s gripping.