I've been reading a little about the Dardanelles campaign of 1915; not the famous landings in April but the failed naval campaign which preceded them in February and March. The basic idea was that British and French forces would sweep the Bosphorus clear of mines, knock out the Turkish naval guns on either side of the straits, proceed to Constantinople and then receive Turkey's surrender. In the event, the first two parts of this plan failed rather spectacularly (three battleships were lost to mines in a single day), but even if they hadn't, just how a fleet of warships was supposed to make a country surrender has never been very clear, at least not to me.
It's tempting to see this as a sort of naval knock-out blow. Constantinople, the Turkish capital, would be under the guns of the Allied battleships. Turkey had no significant navy of its own, besides the ex-German battlecruiser Goeben which would have been hugely outnumbered, so the city would be open to a devastating naval bombardment. So perhaps the sheer moral effect of this would cause a collapse. And it seems the Turks feared this. On 18 March, the day of the attempted breakthrough, according to Robert Massie:
Meanwhile, in Constantinople, the government and the populace were convinced that the Allied fleet would break through. All Turks respected the near legendary power of the British navy; no one believed that a collection of ancient forts and guns at the Dardanelles could bar its way. Accordingly, word of the massive bombardment precipitated an exodus from the capital. The state archives were evacuated and hidden; the banks were emptied of gold; many affluent Turks already had sent their families away. The distance from Gallipoli to Constantinople was only 150 miles; most Turks expected that less than twelve hours after they entered the Sea of Marmara, British battleships would arrive off the Golden Horn.1
So if a moral effect was intended, it seems like it was starting to work. But as I say, it's frustratingly unclear in the histories and biographies I have to hand just what the Allies expected was going to happen. There's a suggestion that Kitchener thought the morale of the Turkish army would break; maybe there would be another revolution; or maybe the soldiers eventually landed at Gallipoli could have been used to take Constantinople instead. Of course, there would have been other benefits from forcing the straits: opening the sea lanes to Russia, foremost among them.
Whether or not the Dardanelles operation was supposed to have been a naval knock-out blow, it may have had some influence on the development of the aerial knock-out blow. Frederick Sykes was a relatively early believer in the power of strategic bombing, as far as the RAF was concerned, but even the exhaustive semi-biography by Eric Ash doesn't pin down when he did adopt it. (Ash suggests before the war, but doesn't really show this.) But from July 1915, Sykes was the commander of the RNAS in the eastern Mediterranean, including the Dardanelles. He would have been aware that Constantinople was the ultimate objective of the campaign, and he did in fact propose bombing the city from the air to undermine Turkish morale and interdict supply.2 Perhaps this problem of how to get at Constantinople, and maybe rumours of the panic in March, got him thinking about the potential power of the bomber in ending a war? The same applies to P. R. C. Groves, who was Sykes' chief of staff, and would again be his subordinate in 1918 when they were the RAF's Chief of Air Staff and Director of Flying Operations respectively, and were very keen to bomb Germany as hard as possible. I've looked at Groves' papers, however, and there's not enough evidence there to say whether he believed in anything like the knock-out blow before late 1917. All I can say is that the lure of Constantinople could have been one influence on the air extremism of Groves and Sykes.