I misunderstood, ethics aside why would you think this is a good strategy? From the cases I remember sanctions are making thing worse, are there any examples of sanctions working out as 'intended'?
Examples of an economic blockade hurting economically a military power?
I would need to double-check, but I'd be surprised if it didn't hurt Napoleon's army, as well as Hitler's and Mussolini's, for instance. I remember that one of the reasons for which the Allies won WWII is that towards the end of the war, the Wehrmacht had considerable difficulties finding fuel for their panzers and logistics and had insufficient ammo for extended fights.
edit Clarified.