1960s movie on Texan War of Independence

At the beginning of this movie some people discuss various possible remakings of the map of North America. At the end troops are riding to battle under the Lone Star Flag; the star gets nearer and nearer till it fills the screen, then recedes to reveal itself as one of the stars in Old Glory; then one of the stars flashes a while. What was the movie called, and is there any place I might see it again?