YAN’AN, China — In 1944, a group of American diplomats in a beat-up C-47 propeller plane swooped down onto a rocky runway in Yan’an. Their mission was to assess Mao Zedong, who had made the city in northern China his guerrilla redoubt, and judge whether he deserved American backing.

Some of the Americans concluded that because Mao had the support of the people, he would have the upper hand in the inevitable civil war with Chiang Kai-shek, viewed by Washington as obstinate and corrupt. They were in favor of the United States throwing its weight behind Mao.

For that judgment, they saw their careers destroyed during the McCarthy era. They became victims of the witch hunt for so-called Communist sympathizers and those who “lost” China.

But to this day in Yan’an, they are heralded as the good Americans who understood China, and are even featured in a museum and compound here that eulogizes the Communist Party’s embattled origins and endurance.