Would Biden dare to go to Kyiv?

After Boris Johnson's bold trip to Kyiv and his walkabout around the city, there are all kinds of reports whistling around Washington about the need for a high-up American official to do likewise to demonstrate solidarity with Volodymyr Zelensky, the embattled but gloriously pugnacious Ukrainian president. Could it be Joe Biden himself or would that be a step miles too far for his Secret Service team? If he did go I can't see him walking around the streets of Kyiv as casually as Boris did. He only seemed to be accompanied by a handful of armed Ukrainian special forces bodyguards, whereas Biden would need the full security gamut. It would involve hundreds of troops. Too much risk? The alternative options are for either Antony Blinken, the cool secretary of state, or Lloyd Austin, defence secretary, to make the trip to Kyiv. But would Zelensky feel rebuffed if Biden doesn't make it to his capital city? I suspect the Ukrainian leader will be happy with whoever Washington sends because it will be a huge boost to his leadership status. But there is no question that the arrival in Kyiv of the president of the United States would be an absolutely massive PR moment. Putin would be furious which would be good. In 2008 Nicholas Sarkozy, then the French president, made a dramatic and obviously previously unannounced visit to Kabul to meet the Afghan leader and talk to French troops. It was quite a coup for him and typical of the man. Will Biden dare to follow suit with a wizzbang visit to Kyiv?