It's true that Cameron, the BOE, and the Fed* could do things to help the Eurozone and to some degree indirectly help themselves, though I have a hard time seeing just how the politics of helping Yurp indirectly while not helping yourselves directly make any sense, or how the reaction function of the ECB would be anything less than sociopathic.
*I exclude Obama because his hands are, at the moment, somewhat tied.
