Three weeks after a Chinese balloon was sighted over the United States and almost a fortnight after it was shot down, Joe Biden said on Thursday that he wanted to talk to Xi Jinping about it. “I expect to be speaking with President Xi. I hope we are going to get to the bottom of this, but I make no apologies for taking down that balloon,” he said. Since the 60m Chinese balloon floated across North America from Alaska to the Atlantic Ocean off South Carolina, the US has shot down three other objects above its airspace, although Biden said…