In the house where I grew up, President Nixon was a villain. My parents voted against him every opportunity they got, and we all cheered when he resigned during his second term, flying off in ignominy from the White House lawn to a life outside the public eye. That he was a criminal, a warmonger, a bigot, a vicious redbaiter, a threat to the Constitution — these were unquestionable truths. So for me, a recent visit to the Richard M. Nixon Presidential Library and Museum in Yorba Linda was a head-turning, mind-bending experience that challenged my assumptions and forced me...