‘Patriot battery will be under US command, but Mr Tusk said Warsaw would be interested in buying dozens more such systems, in addition to “many more” F-16 jet fighters to protect Polish airspace. The missile defence base would also involve the first permanent stationing of US troops in Poland, which Mr Tusk said meant “Poland will no longer be in the sphere which is not directly defended”.

The thing about Eastern Europe is that the borders have changed several times in the last century or so, each time at a high price in blood. Poland especially. Once the economic boom fades, the old insecurities come back.