Why did the United States go to war in Vietnam? One would think this question would have a definitive answer by now, but it continues to provoke a cascade of questions. Was the war avoidable? If not, was it winnable? If not, was there was an alternative strategy that could have been more successful? And if not, why did American leaders commit so much blood and treasure, not to mention their own careers, to a lost cause?

There are many answers to these questions, but no consensus. To borrow the title of a major book on the war, the question of why the USA fought the Vietnam War lies at the heart of an ‘argument without end’.

It is entirely fitting that one of the authors of Argument Without End (1999) was Robert S McNamara, the secretary of defence in the 1960s. He helped make the war happen and his career was sacrificed on the funeral pyre of its failures. He was so integral to all aspects