During World War II, the Allies sent supplies to the Soviet Union via Murmansk/Archangelsk in the north, via Persia and the Caspian Sea in the south, and via the Tran-Siberian railroad.
Why didn't the Allies use these routes in World War I, instead of trying to force a passage through the Turkish straits via the Dardanelles?
Conversely, if the Dardanelles was so key to the Allied war effort, why didn't they send enough troops and ships to do the job instead of making a half-baked effort that was likely to fail?