Originally posted by Heyesey
Won't be much use to them once Turkey is defeated and the British occupy the Black Sea. They can just torch the wheat fields.
A large naval power will always defeat a large land power in the long run, because the naval power can blockade, and cannot itself be damaged in return. The English figured this out in the 16th century, which is why they expended so much effort on being the world's leading naval force for 400 years afterwards. At the time of WWI, the British naval fleet was still more than twice as large as anybody else's in the world, and eventually it *would* have ground Germany into submission. Might have taken another ten years, but after already losing a million men, they're not going to give up now 
It was largely an understanding of exactly this outcome that led the Germans to begin an all-out Uboat campaign against civilian shipping, which in turn led to the Americans joining the war (Lusitania, anyone?) They knew by then that it was shit or bust, and whether or not the outraged Americans joined in against them wasn't going to matter to the eventual result. They failed to do enough damage to British shipping, the outraged Americans did join in against them, and it all got wrapped up a good deal more quickly.
Actually, Heyesey, this is a fascinating thought exercise. The assumptions are that the US is removed from the equation completely, and assume that Germany, after defeating Russia, was able to move enough men to the west in order to achiive a decisive breakthrough in France in mid-1918, knocking France out of the war. What happens next? It all depends on how the British retreated during the break-through. I would would say that the odds that they retreated towards Normandy and the Channel ports is overwhelmingly high; but by doing so they would likely doom Italy. But the British aren't going to risk their army being cut off and surrounded in France, so they will of course move towards the ports and the protection of the navy. Presumably, the Germans in the terms of the armistice will not allow the French to allow the British to move men across France towards Italy, meaning that to redeploy their men in order to help their Italian allies, the British will have to sail them from Normandy and England through Gibraltar to Italy. Gibraltar would become a bottleneck, and in all probablilty, just about every German U-boat would be moved there to hamper the redeploymwnt of troops. Germany and Austria-Hungary, meanwhile, using interior lines of communication, would be able to quickly send men by railroad through southern Germany and Austria to the Italian front while the British hare taking the longer, slower, and more attritive route around Gibraltar. The end result would be that the Germans would be able to concentrate much of their army on the Italian front before the British would be there in significant numbers. I would say that by the end of 1918, the Italians would be desparately trying to reform their armies behind a hurredly created defensive line on the Po and the outskirts of Milan (at best). I don't see Italy lasting more than a few months after the fall of France, and that's if they don't throw in the towel almost immediately. So, by this point, of all the allies, only Britain and associated states are left...
That means that at that point, the only front left to fight in is in the Near East. Greece, seeing how the tide is turning, would attempt to reassert its neutrality and demand that the Britsh forces at Salonica withdraw, and would likely call in the Germans if they didn't leave immediately. That would only leave the front in Syria and Mesopotamia as the only active fighting fronts. Once again, the Germans would redeploy through Tukey, along the infamous Berlin-Baghdad railroad they built for just such a purpose...
It all comes down to morale at this point. Germany has defeated all its foes except for Britain, so even though the cost of the war has been high, victory is in sight and morale would be high. Britain, on the other hand, is now fighting alone and all her allies have been defeated. It would only take a few defeats in the Near East to convince people that the war is lost and it would be best to come to terms now before the situation becomes worse. And remember, to get men to the Near East, the Britsh have to ship them through the bottleneck at Gibraltar, where the Germans would be sending all the U-boats available to make the cost of such a movement high. The Britsh dare not send a lot of ships to protect the transports, becasue they run the risk of weakening the North Sea fleet to the point that the Germans might actually come out and fight. In my opnion, the Germans get more troops to Syria and Mesopotamia faster than the British, and their morale would be higher. A few quick defeats, resulting in the recapture of, say, Damascus and Baghdad, especially if the Suez Canal is lost, and Britain would likely sue for peace.
