When the presidents and prime ministers of the Group of 20 nations met in Rome this weekend, China’s leader, Xi Jinping, was not among them. Nor is he expected at the climate talks this week in Glasgow, Scotland, where China’s commitment to curbing carbon emissions is seen as crucial to helping blunt the dire consequences of climate change. He has yet to meet President Joe Biden in person and seems unlikely to anytime soon.

Xi has not left China in 21 months — and counting.

The ostensible reason for Xi’s lack of foreign travel is COVID-19, though officials have not said so explicitly. It is also a calculation that has reinforced a deeper shift in China’s foreign and domestic policy.