Why would he wish to stop the French-German axis?
To prevent world war that will automatically involve US. You know, France and Germany are part of NATO and what they already achieved in Europe is thanks to NATO. It means that US of idiot Bill Clinton, sided with Islamic league and western Europe already involved US in some `wild projects`. What we see is that Trump obviously informed Merkel and Macron that he (and magnates behind him) aren`t ready to sacrifice US and whole world for the greed of France and Germany and their desire to rule over other Europeans who do have right not to be ruled by France and Germany.
See, official Poland and many other countries peacefully gave up their sovereignty and attached itself as regions in that new French-German Empire. But my country, for example, giving serious resistance and pays great price to preserve its freedom. In that struggle, my country called for support entire world willing to support our right not to be ruled by French-German axis. Many world powers, one after another responding positively. So, quite possible that US under President Trump also concluded that by helping to European countries like my country, US actually returning to its main mission in the world- and that will be to support freedom.