Robert Kagan: “But even Trump must know the likely response in Europe. The insults and humiliations he inflicted on allied leaders will not be forgotten or forgiven. They will make it impossible for European leaders to win public support for the spending Trump disingenuously claims to want. What German leader after such a tongue-lashing could do Trump’s bidding and hope to survive politically?” “Any student of history knows that it is moments like this summit that set in motion chains of events that are difficult to stop.