a riddle, wrapped in a mystery, inside an enigma

That which is so dense and secretive as to be totally indecipherable or impossible to foretell. It is from a line used by Winston Churchill to describe the intentions and interests of Russia in 1939: "I cannot forecast to you the action of Russia. It is a riddle, wrapped in a mystery, inside an enigma; but perhaps there is a key. That key is Russian national interest." Many versions, variations, and appropriations of the quote, its structure, and its meaning have since been in use. Political campaigns make my head hurt. They're just a riddle, wrapped in a mystery, inside an enigma.