The EU is having a tough time keeping it together.
After the ISIS migration, the attacks in Paris and now possible World War with Russia.... Poland wants out.
That makes no sense. Poland isn't trying to get out of NATO so it will still be tied militarily in the event of a war with Russia, and to the extent that it has broken with the rest of Europe it's because Poland has pushed for a tougher line on Russia.
Second, if Poland left the EU its economy would collapse. I don't think anybody could possibly rebut that. The only possible solution would be if the Euros agreed to allow Poland to have all the benefits of EU membership (trade, investment, freedom of labor and capital) without having to actually be members. I don't see that happening.