Military historian Max Boot's new book asks if the Vietnam war could have been won if CIA operative Edward Lansdale's advice had been heededI was with an acquaintance who had participated in the agency’s secret air operations in Laos during the 1960s. After exchanging cards, my friend popped a question: Did Colby think that history could have been changed and over a million deaths averted if the US had accepted Ho Chi Minh’s offer of an alliance at the end of World War II? Colby, who oversaw a CIA counter-insurgency program in Vietnamese villages that killed upwards of 40,000...