 The U.S. government was also anxious to show Union presence along the Mexican border since the French army had just invaded Mexico and installed Maximillian as emperor.Following the Union debacle at the second Battle of Sabine Pass, the U.S. government demanded General Nathaniel P. Banks, commanding the Department of the Gulf, to make another attempt at invading Texas.Nathaniel Banks assembled 6,000 soldiers from three brigades in Napoleon J. T. Dana's XIII Corps.