The greatest danger is not outside pressure but inner conflicts about the function of the EU. Free trade zone? With or without synchronised foreign trade policies? Political union? With or without financial equalisation? Military alliance? With or without EU forces?
The conflicts are as old as the Rome treaty, but the current problems (financial crisis, refugee influx, Brexit, Ukraine) revealed them like a potato reveals the innards of a watermelon.
I am still cautious optimistic. With luck not only wishful thinking.
