(1) Policy shifts occurred where bargains were struck among diverse societal actors. Where concessions were not forthcoming (Britain) or fell apart (the Popular Front in France), orthodoxy continued.

(2) Policy shifts occurred where proposals had the legitimacy of mass support (democratic or mobilized from above).

(3) Crisis was itself a catalyst of change (even in orthodox Britain).

(4) Strong party systems were crucial. Where they failed (Weimar Germany), policy shifts were not possible.

(5) Military insecurity and nationalism reinforced policy shifts.