"The Euro zone crisis is a more dramatic manifestation of the European malaise because its founders created a system in which each of its members has the capacity to bring it down, with appalling costs to themselves and the entire neighbourhood.
If we are not willing to risk a partial dismantling of the EU, then the choice becomes as stark as can be in the lives of federations: deeper integration, or collapse." From a speech in Berlin by Polish Foreign Minister Sikorski in 2011.
The excerpt can be found in the Epilogue to my book, attached as PDF document (and missing in the published version). The malaise in these last four years has only become more serious as manifest in the Greek crisis, the migrants crisis, the Ukrainian crisis and the North-South crisis inside the EU.