Two Flags West

Two Flags West is a 1950 Western drama set during the American Civil War, directed by Robert Wise and starring Joseph Cotten, Jeff Chandler, Linda Darnell, and Cornell Wilde. The opening credits contain the following statement

In the autumn of 1864, remnants of the Confederate 5th Georgia Cavalry are prisoners of war in the Union prison camp at Rock Island, Illinois. Sick and dying in deplorable conditions, they find a chance for survival when Union Captain Mark Bradford Cornel Wilde offers them release from this stinking pesthole if they will join the Union Army to garrison a fort on the western frontier, undermanned because its ablebodied regulars have been sent east, leaving only greenhorns or casualties like Bradford to fight Indians. Although promised that they will not be compelled to fight against their own, many of the Georgians resist the offer. Putting the decision to a vote, the issue is deadlocked when the last soldier dies before he can choose. Compassion for his men, and Bradfords sincerity, compels their reluctant commander, Col. Clay Tucker Joseph Cotten to break the tie by agreeing to the conditions offered.The troop arrives at Fort Thorn, New Mexico, a small outpost of the 3rd Cavalry. Their welcome from the post commander, Major Henry Kenniston Jeff Chandler, is stern and provocative. The bitter Kenniston has a limp from a wound that relegated him to Fort Thorn early in the war. Tucker, now a lieutenant in the Union Army, dines with Kenniston, his widowed sisterinlaw Elena Linda Darnell and civilian guests, and is put on edge by their patronizing comments. Tension becomes high when Tucker reveals that he led the cavalry charge that killed Elenas husband. Elena has been stranded for months at the fort on her way home, and is uneasy with her brotherinlaws protectiveness, suspecting that he believes himself to be his late brothers surrogate. ........

Source: Wikipedia