House speaker Nancy Pelosi’s visit to Taiwan, and the rising tensions with China that it’s fed, are fairly complicated issues.

After a series of careless statements by President Joe Biden and ramped up US military activity off China’s coast, Pelosi’s visit is the latest test of the long-standing US policy that’s underwritten stable US-China relations for decades. That is, that Washington officially views Taiwan not as an independent country but as part of China, supports the general concept of their eventual reunification, but reserves the option of defending it militarily if China uses force to retake the island.

China has always bristled at any US actions that seem to move the country away from this doctrine and closer to open recognition of Taiwanese sovereignty — given its firm belief that Taiwan is Chinese territory — but has historically been too weak to do much about it. But as an ascendant economic and military power today, China is more assertive in pushing back, and Pelosi made her visit in direct defiance of warnings from Chinese leadership. It also comes in the context of years of heated, bipartisan US rhetoric singling out China as a threat.