vicious circle

noun

1. A situation in which the response to one problem creates a chain of problems, each making it more difficult to solve the original one.

   “Meanwhile street congestion grows worse and the vicious circle tightens of private motor-cars which impede L.T.E. buses in Central London and of exasperated bus travellers who therefore take to using their own cars.”

2. A fallacy in which the premise is used to prove a conclusion which is then used to prove the premise.