EARLY October is probably the nicest time of the year in Washington: not too hot, not too cold, only a shirt needed in the daytime, a pullover in the evening. The leaves on the trees in the US capitals famed Mall have just started to turn a glorious gold. On the only afternoon that I have off, my steps take me to the Vietnam War Memorial, located on one side of the Abraham Lincoln Memorial. It was not there when I was last in Washington, accompanying Rajiv Gandhi in his press party during his hugely successful 1985 foreign tour. The two memorials are a study in contrast, the Lincoln Memorial a throwback to the grand Roman and Greek classical age, which inspired the early American architects, and the Vietnam War Memorial a modern classic, designed, I believe, by an American-Chinese architect.