Now WI the Commonwealth forces won at Gallipoli? The British would have that landing they wanted, but the problem is the Turks are not going to simply stand down. Can we expect trench warfare deeper into turkish land, or would it really be the knockout blow everyone expected?
Well, first one must define what "win" means. If a British win at Gallipoli means that the Dardenelles and Constantinople are under British control, then I think that it would the knock-out blow to the Turks. The Brits would now be able to move supplies through the Dardenelles into Russia, and keep them in the game. It would also have very interesting effects on the Arab Middle East. In 1915 the Sykes-Picot agreement between the British, French and Russians, had not yet been signed, but the agreement with Sharif Hussein for a united Arab kingdom covering OTL Syria, Jordan, Lebanon, maybe Israel-Palestine, and Saudi Arabia, had already been made. I don't know if the Turks would throw in the towel, but they would certainly have suffered a massive setback, and I think that retaking Constantinople ranked much higher than fighting Arabs.
So Russia stays in the war, the war probably ends early with no American involvement, and the Arabs are able to establish their own Kingdom under British protection.
Thoughts?