Ireland under Home Rule must, in the event of war, be regarded as a potentially hostile country.
In this statement resides the dominant factor of the situation viewed from the naval and military point of view. It is not asserted that the government of Ireland would be disloyal; but it is asserted that the authorities charged with the defence of his Majesty's dominions cannot afford to take risks when the safety of the country is at stake. That such risks must exist under the circumstances indicated, is obvious to all those who have studied the speeches of the leaders of the Irish Nationalist party, in which they have unequivocally declared their intention to rid Ireland of English rule, and in which they extol as heroes such men as Theobald Wolfe Tone, who intrigued with France against England in order to achieve Irish independence, and who took his own life rather than receive the just reward of his deeds. That some among the Irish Nationalist leaders have recently professed their devotion to the British Empire cannot be regarded by serious persons as a relevant consideration. The demand for Home Rule is in fact a demand for separation from the United Kingdom or it is nothing. Naval officers are accustomed to deal with facts rather than with words.
In the great sea-wars of the past, Ireland has always been regarded by the enemy as providing the base for a flank attack upon England. Had King Louis XIV. rightly used his opportunities, the army of King William would have been cut off from its base in England, and would have been destroyed by reinforcements arriving from France to assist King James II. There is no more concise presentment of the case than the account of it given by Admiral Mahan in "The Influence of Sea Power upon History, 1660-1783."
"The Irish Sea, separating the British Islands, rather resembles an estuary than an actual division; but history has shown the danger from it to the United Kingdom. In the days of Louis XIV., when the French navy nearly equalled the combined English and Dutch, the gravest complications existed in Ireland, which passed almost wholly under the control of the natives and the French. Nevertheless, the Irish Sea was rather a danger to the English—a weak point in their communications—than an advantage to the French. The latter did not venture their ships-of-the-line in its narrow waters, and expeditions intending to land were directed upon the ocean ports in the south and west. At the supreme moment the great French fleet was sent upon the south coast of England, where it decisively defeated the allies, and at the same time twenty-five frigates were sent to St. George's Channel, against the English communications. In the midst of a hostile people the English army in Ireland was seriously imperilled, but was saved by the battle of the Boyne and the flight of James II. This movement against the enemy's communications was strictly strategic, and would be just as dangerous to England now as in 1690[67]....
"There can be little doubt that an effective co-operation of the French fleet in the summer of 1689 would have broken down all opposition to James in Ireland, by isolating that country from England, with corresponding injury to William's power....
"The battle of the Boyne, which from its peculiar religious colouring has obtained a somewhat factitious celebrity, may be taken as the date at which the English crown was firmly fixed on William's head. Yet it would be more accurate to say that the success of William, and with it the success of Europe, against Louis XIV. in the war of the League of Augsburg, was due to the mistakes and failure of the French naval campaign in 1690; though in that campaign was won the most conspicuous single success the French have ever gained at sea over the English."
Every great naval power has gone to school to Admiral Mahan; and this country can hardly expect again to profit by those mistakes in strategy which the gifted American writer has so lucidly exposed.
Ireland, lying on the western flank of Great Britain, commands on the south the approaches to the Channel, on the west the North Atlantic; and on the east the Irish Sea, all sea-roads by which millions of pounds' worth of supplies are brought to England. On every coast Ireland has excellent harbours. There are Lough Swilly on the north, Blacksod Bay on the west, Bantry Bay, Cork Harbour and Waterford Harbour on the south, Kingstown Harbour and Belfast Lough on the east—to name but these—besides numerous lesser inlets which can serve as shelter for small craft and destroyers. It should here be noted that Belfast Harbour, owing to the enterprise of the Harbour Board, now possesses a channel and dock capable of accommodating a ship of the Dreadnought type[68].
There is no necessity to presuppose an actively hostile Ireland; but an Ireland ruled by a disloyal faction would easily afford shelter to the warships of the enemy in her ports, whence they could draw supplies, where they could execute small repairs, and could coal from colliers despatched there for the purpose or captured. Thus lodged, a fleet or a squadron would command the main trade routes to England; and might inflict immense damage in a short time. Intelligence of its position could be prevented from reaching England by the simple method of destroying wireless stations and cutting cables.
These considerations would necessarily impose upon the Navy the task of detaching a squadron of watching cruisers charged with the duty of keeping guard about the whole of Ireland.