With the western front in stalemate by the end of 1914, the triple entente's military leaders began to think of ways to circumvent the deadlock. Winston Churchill, then First Lord of the Admiralty, petitioned for a military offensive to secure the strategically important Dardanelles straits, a 30-mile long channel that linked the Aegean to the Black Sea. Controlling the Dardanelles would enable the allies to resupply the beleaguered Russians, capture the Ottoman capital Constantinople and potentially even attack Germany's Baltic coast.
The lure proved too strong for Churchill, who forgot the assessment he had made in 1911 -- that "it is no longer possible to force the Dardanelles, and nobody would expose a modern fleet to such peril." Churchill also disregarded numerous warnings from Admiral Carden, the commander of the British Navy in the Mediterranean, that the Turkish defences on the peninsula of Gallipoli would prove invulnerable to naval gunfire alone.
Such warnings proved apposite, and the consequences for the land invasion were tragic. Allied casualties are estimated at around 265,000 and Turkish at approximately 216,000. In his book History's Worst Decisions, Stephen Weir chronicles an operation beset by errors from the outset, noting that "half the Australian forces landed on the wrong beach". At the time, the failed attack was put down to a combination of "bad luck, muddle, [and] indecisiveness".
Weir, though, is more damning in his analysis of the disastrous campaign: "Itching to get into the fray somehow...it was little more than pride and vainglory that propelled Churchill onward into the fiasco that followed."
Discredited, the future prime minister was temporarily expelled from both the War Cabinet and the government.