House Speaker Kevin McCarthy met with Taiwan’s President Tsai Ing-wen in California today, despite Beijing’s threats of “retaliation.”

Republican McCarthy, by virtue of his office, is third in the US political hierarchy after President Joe Biden and Vice President Kamala Harris. He is the most senior American politician to meet with a Taiwanese leader on American soil since 1979.

Protesters, some pro-Beijing, some pro-Taiwan, had gathered outside the Ronald Reagan Presidential Library in Simi Valley City as Tsai arrived. Officially, the president of Taiwan was “in transit” from the US, on her way back to Taipei from her tour of Latin America.

Some of those gathered held Taiwan and Hong Kong flags and chanted “Jiayou Taiwan” – loosely translated as “Forward, Taiwan”.

This meeting angered Beijing and the Chinese authorities threatened to “retaliate”. China considers Taiwan its province, and while it says it would prefer a “peaceful reunification” of the mainland with the island, it has not ruled out the use of force. Based on the “one China” principle, no country can maintain official ties with Beijing and Taipei at the same time. On Monday, the State Department reiterated that China “strongly opposes” McCarthy’s meeting with Tsai and said it was ready to “defend its national sovereignty and territorial integrity.”

The US has for years maintained an “ambitious strategy” on the issue of Taiwan. The doctrine they follow is aimed at discouraging a Chinese invasion of Taiwan and preventing the island’s leadership from provoking Beijing by formally declaring its independence.

Last August the president of Taiwan welcomed the then Speaker of the House Nancy Pelosi in Taipei. This meeting angered Beijing, which responded with military exercises on an unprecedented scale around the island.