In the card game of euchre, the knave of the trump suit is highest.
When one comes up short in a transaction under suspicious circumstances the euphemism that arose from the game is "I was euchred." Swindled.
Various European states that were cajoled into joining the EU appear to be saying they were EUchred and want out.
I find it humorous to see it this way: The knaves in the EU hate the Donald primarily because he seems to have turned out to be the wild-card that Trumps them.
The states of the EU have noticed.