EU flag

The European Union is a political organization consisting of 27 European states including the United Kingdom, France and Germany, the European Union declared war on the Russian Federation when Al-Qaeda and the Nazi Cult disguised as Russian and Ukrainian soldiers attacked Poland, starting World War III

In the Campaign mode, the European Union is not entirely at war, only a number of different nations, primarily the UK, France, Germany, Belgium, Denmark and Turkey, the other nations are not involved for multiple reasons, either voted against war or invaded by the Russians, it is unkown.