Complex sentence: Members of the Lao Veterans of America served in the U.S. clandestine war in the Kingdom of Laos during the Vietnam War that included support for key U.S. covert air and ground operations including Operation Barrel Roll against the North Vietnamese Army and communist Pathet Lao forces.
Split into simpler sentences: Members of the Lao Veterans of America served in the U.S. clandestine war in the Kingdom of Laos during the Vietnam War. They engaged in combat operations, and provided support, for key U.S. covert air and ground operations including Operation Barrel Roll against the North Vietnamese Army and communist Pathet Lao forces.