Hate to use wiki, but this is interesting:

"Perot became heavily involved in the Vietnam War POW/MIA issue. He believed that hundreds of American servicemen were left behind in Southeast Asia at the end of the U.S. involvement in the war, and that government officials were covering up POW/MIA investigations to avoid revealing a drug-smuggling operation used to finance a secret war in Laos."

wikipedia.org/wiki/Ross_Perot