With Washington and its allies distracted by the pandemic and its economic fallout, Mr. Xi is taking bold steps on issues where he’s often faced international pushback, including Hong Kong, Taiwan, the South China Sea and a disputed border with India.

“The top leadership thinks China is relatively strong compared to the U.S. at the moment,” said Shi Yinhong, a Chinese government adviser and professor of international relations at Beijing’s Renmin University. “Of course they see this as a strategic window of opportunity.”…

A long-running border dispute between China and India flared again in the past few weeks after Chinese troops moved into a contested Himalayan area close to where India has been upgrading infrastructure, prompting fistfights between the two sides.

Beijing has further upset the status quo in the South China Sea in recent weeks. It created two new administrative districts in contested areas, named 80 geographical features there—the first such Chinese move since 1983—and sent ships into waters off Vietnam and Malaysia.