When Richard Nixon returned to Washington after his historic 1972 trip to China, he was welcomed with strong support from Democrats. “From the initial Congressional reaction, it was apparent that the President, home from his China trip, would find broad bipartisan support for his move toward closer relations with Peking,” The New York Times reported on Feb. 29, 1972. Even Democratic Senate leaders Edward Kennedy and Mike Mansfield praised Nixon’s diplomatic gamble. Forty-six years later President Donald Trump took a similar political risk in agreeing to the first ever summit with a North Korean leader. Cautious optimism emerged from the...