Complete the sentence with a suitable expression from the collocation box. Adj + alliance: close, formal, loose, political, powerful, strategic Adj + destruction: complete, environmental, total, widespread Adj + factor: critical, decisive, important, key, major, relevant Adj + opportunity: considerable, golden, little, unique Adj + protest: angry, formal, official, peaceful, political, public, strong V + frustration: cause, express, increase, hide, suffer In the last years of the 20th century, there was a(n) _____ _____ to bring back enthusiasm and idealism into politics.