Biden has emphasized building lines of communication with China to "responsibly manage" their differences. A November meeting between Xi and Biden yielded an announcement the two governments would resume a range of dialogues that China had shut down after an August Taiwan visit by then-House Speaker Nancy Pelosi.
Last weekend, the US cancelled what would have been a relationship-building visit by Secretary of State Antony Blinken after the transit of the Chinese balloon, which the US says was for espionage. China claims it was a civilian balloon used for meteorological research.
The same week that China's balloon flew over the US, Austin was in the Philippines to announce an expanded US military footprint there, neighbouring China, noted Tiehlin Yen, director of the Taiwan Center for Security Studies, a think tank. "America is also very nationalistic these days," Yen said.
"From a regional security perspective, this dialogue is necessary," Yen said.
What passes for military and civilian hotlines between China and the US aren't the classic red phones on a desk
Under a 2008 agreement, the China- US military hotline amounts to a multistep process by which one capital relays a request to the other for a joint call or videoconference between top officials on encrypted lines. The pact gives the other side 48 hours and up to respond, although nothing in the pact stops top officials from talking immediately.
Sometimes when the US calls, current and former US officials say, Chinese officials don't even pick up.
"No one answered. It just rang," recounted Kristen Gunness, a senior policy analyst at the Rand Corporation. Gunness was speaking about a March 2009 incident when she was working as an adviser to the Pentagon's chief of naval operations.
Chinese navy vessels at the time surrounded a US surveillance ship in the South China Sea and demanded the American leave. US and Chinese military officials eventually talked - but some 24 hours later.
Reluctant to use it in any substantive purpose
It took decades of Washington pushing to get Beijing to agree to the current system of military crisis communications, said David Sedney, a former deputy assistant secretary of defense who negotiated it.
"And then once we had it in place, it was clear that they were very reluctant to use it in any substantive purpose," Sedney said.
Americans' test calls on the hotline would get picked up, he said. And when Americans called to give congratulations on some Chinese holiday, Chinese officials would pick up and say thanks, he said.
Anything more sensitive, Sedney said, the staffers answering the phone "would say, 'We'll check. As soon as our leadership is ready to talk, we'll get back to you.' Nothing would happen."
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