Excuse me Mr Putin, the president of the United States is on his way

One of the more sobering things about superpower politics is that there is always the world-changing danger of a nuclear war catastrophe because of a serious miscalcuation or, worse still, an error of megaton significance. I am referring to the bizarre but somehow comforting fact that a couple of hours before President Biden in huge secrecy arrived by train in Kyiv from Poland to see Volodymyr Zelensky, the Kremlin was officially warned of the imminent trip so as to avoid any possibility that Moscow might order a missile attack on the Ukrainian capital. With or without knowledge of Biden's presence in Kyiv, a missile strike which killed the president of the United States as he was engaged in a walkabout in the city would have been so disastrous that it could just have led to the Third World War. So, better to tell the Kremlin through the usual high-powered channels rather than risk an assassination either by error, by coincidence, or by devious intention. Putin got the message and sure enough there was no missile strike on Kyiv during the five hours Biden was there, although a MiG-29 took off and started flying in that direction setting off air raid alarms across the country. That was probably Putin's way of saying to Biden, "ok this time but I was tempted". So all in all it was quite reassuring that Putin has not lost all his marbles. He hasn't loosed off tactical nukes against Ukraine because he knows from persistent warnings from Washington that were he to do so the consequencees would be too dire to contemplate. Likewise he knew that if he tried to target Biden in Kyiv, even if his missile operators missed, he would now be facing military retaliation. Not by Ukraine but by the US. Big time. War is a dirty business but amidst all the slaughter and potential crimes against humanity going on against Ukraine, Putin knows there are some red lines he cannot and should not cross.