"Dog" starts well and ends well, and it has some smart moments in the middle. What more could we want? Channing Tatum is working at a Subway, stuffing lettuce in buns. A young patron becomes enraged because the toppings are wrong: We sense Tatum's repressed anger at the patron's entitlement, and we also sense that Tatum's mind is very, very far away. Soon enough, Tatum is calling his military advisory board, asking (pleading) to be re-deployed to Afghanistan. Then the script gives us a new twist on Homer's Odyssey--something I haven't seen before. Tatum can get the clearance letter he needs--but only if he does a favor for his captain. A friend--gunned down--has left behind a traumatized dog. The dog can't get on an airplane. Tatum needs to drive the dog across the country, to be present at a military funeral; if this drive occurs, then a clearance letter could pop up. You don't need to be Cassandra to make some predictions. Tatum is, at first, a ...