Donald Trump said he would side with Moscow if it attacks a US ally. Russia returned the gesture with an arrest warrant against the Estonian premier.

Putin interpreted the message of the eccentric former North American president clearly and in his own way. If the US moves away from or reduces its involvement with the Alliance, not only Russia would release its forces of conquest, writes Peter Bergen. The Kremlin wants from its entire neighborhood. That is why there is a war against Ukraine, he writes. Bergen: As deterrence erodes, the notion that an attack against one partner, even the smallest, is an attack on all.