America’s 40th president would have loved this — Communist China has just sanctioned the Ronald Reagan Presidential Library in Simi Valley northwest of Los Angeles. What for, and what does it mean to “sanction” an edifice like a library?

The answer is that the library was the setting for a talkfest at which the president of the free Chinese government on Taiwan, Tsai Ing-wen, was the guest of the speaker of the House, Kevin McCarthy.

“This has blatantly violated the one-China principle and the three China-U.S. joint communiques, violated the U.S. government’s commitments on the Taiwan question, and sent a serious wrong signal to the ‘Taiwan independence’ forces,” the Chinese embassy at Washington said. “China expresses strong protest and firm opposition, and will respond resolutely to the wrong move by the U.S. side.” 

While the Reagan Library would no doubt not feel a thing from sanctions, the sanctions would, at least theoretically, block any Chinese accounts of, among others, the former director and the administrator of the Reagan Foundation. The mission of the Library is to “complete President Reagan’s unfinished work and to preserve the timeless principles he championed….” 

Nor was the library the only institution to absorb the blow of China’s wrath. Beijing also sanctioned the Hudson Institute, based at Washington, for having hosted Ms. Tsai as a speaker at New York right after she arrived in America. As with the Reagan Foundation, Hudson’s chairwoman and director were also sanctioned. 

Coming and going, Ms. Tsai was “in transit” while in New York on her way to Guatemala, and in Los Angeles on returning from Belize en route back to Taipei. The Chinese apparently believed her itinerary was a gambit to give her an excuse for meeting influential Americans on her way to and from Central America. 

In what may not have been a coincidence, while Ms. Tsai was in America and Central America, the man who preceded her as president of the Republic of China, Ma Ying-jeou, was in the People’s Republic of China. He visited the graves of his ancestors in Hunan Province, which is the birthplace of Mao Zedong, and also met Communist officials, saying words they wanted to hear. The crux of his message: Taiwan and China are “all China.”

Mr. Ma, returning to Taipei the same day as Ms. Tsai, warned that “Taiwan was moving closer to danger” despite “accusations he was still living in the past,” the English-language Taiwan News reported. Ms. Tsai said simply that Taiwan and China are “not affiliated with each other.” 

Their opposing views reflect differences between those born in Taiwan and those of mainland origin. Ms. Tsai, of Taipei,  is a member of the Democratic Progressive Party. Mr. Ma belongs to the KMT, or Kuomintang, the Nationalist party whose families had fled the mainland as Mao’s Red Army was roaring to victory in 1949. 

While they were at it, the Chinese Communist government also sanctioned the Taiwan representative at Washington, Hsiao Bi-Khim. Taiwan’s de facto ambassador, she was accused of being “a “diehard Taiwan independence element” — that is, in favor of declaring Taiwan an independent country, not just a Chinese province.

Chinese authorities had to have been happy about a division of views that may be more significant than the daily intimidation by Chinese planes and warships.

Taiwan News said China since September 2020 “has increased its use of gray zone tactics by routinely sending aircraft” into Taiwan’s air defense identification zone. The paper defined such tactics as “attempts to achieve one’s security objectives without resort to direct and sizable use of force.”