Starring Matthew McConaughey. Rated 14A

Based on actual events surrounding the American Civil War, Free State of Jones chronicles the growing disillusionment of Confederate soldier Newton Knight (Matthew McConaughey). With a running time of over two hours, writer-director Gary Ross serves up a rambling narrative that tries to pack in a little too much history for its own good.

The film’s initial scenes show great promise. We see the last days of the Civil War from the Confederate side with an unflinching brutality. There are several issues that prompt Knight to rebel against the army that conscripted him, but Ross’s script is at its best when it illustrates how the Confederate army turns on its own people by looting Mississippi farmers of virtually everything they need to survive a harsh winter.

Knight becomes a deserter, convinced that he’s fighting a war to preserve the rich man’s cotton. He ends up taking refuge with a number of slaves in a Mississippi swamp. From there, Knight morphs into a cross between Rhett Butler and Robin Hood, assembling an army designed to fight the injustices he’s witnessed.

And there are plenty of injustices to go around. The story often hums when it takes a more reflective approach, especially when it comes to issues of slavery. The accomplished supporting cast is a big help here, especially Mahershala Ali as a runaway slave and Gugu Mbatha-Raw as the African-American woman Knight falls for. But pretty much everything hinges on McConaughey’s performance. Thankfully, he carries the film with a skillful mixture of grace and grit.

Less fortunately, the story begins to sag about halfway through, when things slow down markedly and there just isn’t enough to keep us more than half interested. Ultimately, this is a noble effort that fizzles out long before it ends.