Would the US come to Poland's aid if Russia invaded?

It has not been a good week for Europe. In a new national strategy document, the Trump administration switched US interests to the Western Hemisphere and downgraded Europe. To emphasise his disaffection with Europe, President Trump said in an interview that European leaders were weak and suggested the European continent was heading for trouble. The head of Nato, Mark Rutte, the secretary-general, seemed to back the warning that Europe might be facing a dangerous security challenge when he warned that it might be at war with Russia within the next five years. While this is an alarming prospect, the purpose behind Rutte’s prediction was to urge European members of the Nato alliance to spend much more on defence to be prepared for such an event. Trump has in the past given the same message, that Europe must share a bigger burden when it comes to defence expenditure. What is new is that Trump has now demonstrated, beyond doubt, that he is no longer as interested as previous presidents were in propping up Europe to protect the alliance from potential adversaries such as Russia, but rather to focus the national strategy towards US neighbours, in particular, Latin America and Mexico, focusing on the threats posed by illegal immigration and drug trafficking. This is a totally different view of the world and fits closely with the president’s America First policy which helped him to get elected for the second time. However, the message is clear for Europe. It must now face a future in which the automatic dependence on the US can no longer be taken for granted. The unavoidable question is: what would the US do under a Trump administration if Russia decided to invade, say, Poland or Lithuania? Under Article 5 of Nato’s founding treaty, an attack on any member of the alliance has to be considered an attack on every member, obligating the whole organisation to come to the rescue. Does the Trump administration’s new focus on the Western Hemisphere indicate that the US would not necessarily come to the aid of, say, Poland, if Russian tanks swept across the border or Russian bombers started to target key installations in the country? In other words, would Trump leave any response from Nato to the Europeans? This would be a huge moment for Europe which has always known in the past that the US, as the leading nation of the alliance, would without question adhere to Article 5 and back Poland against Russian aggression. The problem for Europe is that if the US starts to back away from this cast-iron guarantee of military support, it might persuade President Putin to consider an attack on an eastern European country, gambling that the US might stand back. Then it would be Russia versus Europe. This is surely why Nato chief Mark Rutte gave his dire warning to Europe last week about the urgent need to build up defences to deter Russia. Europe will have to make up its mind whether to hope Trump is bluffing or to go ahead and prepare for war with Russia.