The mongol invasion, The Collaspe of the Roman Empire, the treat of Napealon, the Cold War, - several little historical tidbits that can be used to back up my sacrastic comment
Is that what passes for teaching history in the US these days? Your argument is spurious at best and nonsense at worst failing to take into account that the majority of the populations mentioned merged into the European culture and effectively became European themselves. The Mongols did not pass Hungary, so they hardly 'conquered' Europe. The Russians are European. If you're not counting the slavs and eastern Europe as European, then the sucess of the Mongol invasion against Europe argument dies a death. Napoleon was defeated by other European powers (internal strife settled). The Cold War - Russians.
By your theory, the Americans have never sucessfully defended their nation either, since the native Americans were defeated and the current rulers of the US are not native Americans. Is there even a native American congressman or senator? It was the Europeans that won the war of sucession against other Europeans.

the advance of Islam by the sword
Oh dear, a tiny area of land near Greece is owned by an Islamic power. Europe is surely doomed. Shall we ignore the Reconquista here?

By all means, block caustic comments, but try not to make such bizarre accusations. Europe is the continent that has made modern history and shaped the world.