National Defense: THE STRATEGIC GEOGRAPHY OF THE CARIBBEAN SEA

On the two following pages TIME presents a map of the most important strategic area in the Western Hemisphere: the approaches to the Panama Canal.

Until the U. S. owns a two-ocean fleet—and such a fleet cannot be built in less than seven years—the Canal is the only insurance the U. S. has against leaving one of its coasts undefended against attack. If an enemy should succeed in blocking or capturing the Canal, that insurance would no longer exist. Hence the first paradox of U. S. strategy: the most vital point for the defense of the continental U. S. is an isthmus 1,300 miles south of Miami, Fla.

When a friendly and unthreatened British Fleet policed the Atlantic and made the Monroe Doctrine a working document, defense of the Panama Canal was a textbook subject. The only possible attack was from Japan in the Pacific, and Japan’s No. 3 world Navy had to operate from too far away. Its long supply lines could be cut at will, even by an inferior Navy, from the Philippines, Hawaii, Alaska and, if the Japanese got past the great ocean fortress of Hawaii, by flanking attacks from the U. S. Pacific Coast.

Frontier. Instead of this remote danger of attack from the Pacific, there will be a new and far more serious danger from the Atlantic if Nazi Germany seizes or destroys Britain’s Navy. The only route for an attacker crossing the Atlantic to strike at the Canal is through an area long regarded by most U. S. citizens as a source of rich commerce and a place for sunlit vacations: the Caribbean.

In its island coves and inlets Pirates Morgan, Stede Bonnet and “Black-beard” Teach once lay in wait to raid New World shipping. From the Bahamas, Jamaica and Martinique, Civil War blockade runners made their night-bound, fog-shrouded dashes to Charleston and Wilmington. And in 1898, the Caribbean was invaded by an inept Spanish Fleet. It had the U. S. Atlantic seaboard in a dither of fright until old Admiral Cervera holed up in Santiago, Cuba, finally came out to have his ships shot down like ducks in a shooting gallery by a U. S. Fleet which was short on strategic reconnaissance, long on guns.

But it remained for the late, great Admiral Alfred Thayer Mahan to put down on paper for future Annapolis men the specific doctrine of the area’s importance. “One thing is sure,” he wrote, “in the Caribbean Sea is the strategical key of two great oceans, the Atlantic and the Pacific; our own chief maritime frontiers.”

The Panama Canal can be attacked in three general ways: 1) enemy saboteurs might block its locks or destroy its gates by blowing up a shipful of explosives on an apparently peaceful transit of the Ditch; 2) bombers launched from an enemy carrier at sea might succeed in a surprise raid in smashing lock machinery or breaching the great dam of Gatun Lake, thereby draining the Canal of water; 3) having gained a foothold in the Caribbean area, an enemy might go about systematic destruction of the Canal with large-scale attacks by sea and air.

Constant vigilance by Army and Navy is the only weapon against sabotage or the surprise raid. And if any enemy were not marvelously successful in his first attempt he might well fail for good. But operating from bases in the Caribbean he could go about his business much more methodically. The only effective defense is to keep him at a distance. Hence the second paradox of defense. The best way to defend the Canal is to defend seas 1,000 to 2,000 miles beyond the Canal.

Hook. From Florida’s tip to the top of South America the islands of the Caribbean swing in a great hook, its shank extending southeast, its barb curving south and west.

The islands of the hook form a natural line of fine defensive outposts with great stretches of blue water between them and the closest jumping-off places for a European invader: the Azores or the Cape Verde Islands. Thus they are potential operating bases from which the U. S. Fleet and land-based aircraft can range far to sea, spotting and striking at any invader as close to his European base as possible. But while the islands make one of the world’s finest strategic assets, they are also great potential liabilities. An enemy with a toe hold on the Caribbean not only might close the Canal and shut off the Fleet in the Pacific; by destroying the Canal he might also cut off naval elements in the Atlantic from the Navy’s great base on the Pacific side of the Canal at Balboa. And while the Pacific Fleet was exhausting fuel and losing time going around the Horn—a 48-day run—he could make sea and air raids on the continental U. S., might possibly even grab Bermuda, only 700 miles from New York and Philadelphia.

The big advantage of the U. S. in defense of the Caribbean is its short and well-protected supply lines. No invader could come close to duplicating them until he had based himself in the area, close to the rich oil supplies of northern Venezuela and the food supplies of South America.

And with Army bombers and the U. S. Navy vigorously interdicting his supply lines from Europe, setting up such a base would be no cinch. To do so would take a huge fleet which probably would have to get a foothold in South America (preferably on Brazil’s jutting coast 1,000 miles from the Cape Verde Islands) before extending himself to the north.

U. S. communications to the Caribbean lie south along the U. S. coast from the Atlantic seaboard, across the Gulf of Mexico (a near-impregnable American lake) from the oil centres at New Orleans, Houston, Galveston, and down Mexico’s coast via the Canal from the Pacific. U. S. bases along these routes are indicated by U. S. flags, foreign bases by anchors. Air bases in the area are indicated by airplanes —red for land craft, blue for seaplanes.

Keys to Windward Passage. The Caribbean hook consists of three areas which grow progressively more vulnerable from north to south. Northernmost and strongest is the stretch from the Strait of Florida to the Windward Passage between Cuba and Haiti. Florida’s Strait is full of shoals, has well-defined channels, is well within the range of aircraft operating from Tampa, Jacksonville, Miami, Pensacola and dozens of inland fields. To the east the 706 islands of the Bahamas protect it, forming a tactical screen, an ideal area for submarines, destroyers, advanced aircraft bases. Except for attack by an overwhelming naval force, the Florida passage is invulnerable. Five hundred miles east of the Strait, between Cuba and Haiti, lies the Caribbean’s central and most used sea gate: the deep, so-mile-wide Windward Passage. Commanding the passage is the U. S. Navy’s leased station on Cuba’s Guantanamo Bay, only a few miles from the rusting hulls of Cervera’s armada.

Its deep harbor can accommodate any units of the Fleet.

Its field is a good base for Navy or Army aircraft. It has no dry docks or major repair facilities. Disabled first-line battleships would have to go north to Norfolk or Philadelphia or pass through the Canal to Balboa for dry-dock repairs. In an emergency the Canal’s locks could be used as dry docks.

Cuba to Leewards. Second section of the hook ranges east to Anegada Passage, between the Virgin Islands and the Leewards. Farther from major U. S. establishments, this defensive sector of the Caribbean is proportionately more vulnerable, but is currently being strengthened. Its strong points are Puerto Rico and St. Thomas. At San Juan a cruiser dock and naval workshop are in construction, and off San Juan Harbor at Isla Grande, a naval air base is being built. Completed, the U. S. defenses at Puerto Rico will also have the eastern striking force of the Army Air Corps, flying fortresses capable of operating more than 1,000 miles to sea from a new field near San Juan. At St. Thomas, V. I., the Marines have an air base and $1,510,000 has been authorized to develop St. Thomas’ fine harbor into a naval station.

Leewards to Venezuela. From this eastern outpost the hook swings on south, to the British-owned island of Trinidad off Venezuela’s northern coast. Trinidad is an operating base to make an invader’s eyes gleam—a bountiful oil and gasoline supply, strategically laid in flank of traffic from South America where he might have a foothold. It would also make an important U. S. outpost, completing the defense set-up of the hook. Its anchorages are deep and wide and its northwest coves would make good seaplane bases. Since it lies well within the U. S. sphere, the British have never developed it as a top-flight operating base. Its dry dock will accommodate nothing larger than destroyers, and it has no landplane base. Near by at Barbados the British have a battleship anchorage, a small airdrome and a tiny dry dock (too small for destroyers). At France’s Martinique there is a small naval and submarine base, a destroyer dry dock. But of first-class base facilities the Lesser Antilles have none. And it is in this section of the hook that an invader reaching for the Canal would almost inevitably make his strongest effort. Between its islands are scores of deep passages, in its coves thousands of spots from which destroyers, cruisers and patrol bombers could operate as soon as field repair facilities and oil-fuel supplies had been laid down. At the western foot of the Lesser Antilles, at Aruba in The Netherlands West Indies, is the world’s largest oil refinery. At The Netherlands’ Curacao near by are good commercial docks and workshops, an ample supply of fuel. Here, in the most valuable and most vulnerable area of the Caribbean, is the first outpost of the U. S.’s maritime frontier.