CAN the United States be invaded? It isn't likely, because we are protected by chains of offshore naval and aviation bases on both oceans. No matter from what direction an enemy fleet approaches he would find himself engaged in desperate battle while still far at sea. There is always, a chance, of course, that, an enemy carrier or two may sneak in from the sea, for a hit-and-run air raid- Some of our offshore bases so far have been liabilities because our defense program, while being rushed, is far from finished. This is the reason for the early Japanese successes in the Pacific. Today the United States is completing a crescent of defense that stretches down the Atlantic from Canada to the Caribbean. Eight new bases leased from Great Britain are being strengthened and these will augment present bases on the mainland and on Cuba and Puerto Rico. In the Pacific, the island of Oahu on which Honolulu is located has become a billion-dollar fortress. That sum has built an impregnable fort, containing our strongest airplane defense base, a great concentration of troops, a multitude of antiaircraft guns and complete naval facilities. Vast stores of ammunition lie in secret underground caches. Military roads have been built to many parts of the 604 square-mile island, some leading to 16-inch gun and heavy howitzer emplacements in the mountains. Pearl Harbor has the world’s largest floating drydock. The harbor is a base for our high seas submarines that have a cruising radius of 15,000 miles. There are facilities for rapidly provisioning and repairing the Navy's scouting and battle fleets. The Hawaiian Islands are not self-supporting and so food enough for a long siege has been stored away. Long ago plans were laid for taking over thousands of acres now inpineapples and sugar and planting other food crops. The reason for the military emphasis on Oahu is that the island commands and protects the whole west coast. Together with Alaska and Panama it forms an invisible but deadly triangle through which an enemy would have to storm his way. Honolulu is 2,400 miles offshore, but that is less than a day’s flight for an airplane, Under as much secrecy as possible, similar defensive activity is being rushed in Alaska. Men in uniform swarm the streets of Anchorage, Fairbanks, and other northern cities. Millions of dollars are being spent for new Army and Navy bases, new submarine stations and tremendous bomber bases up and down the coast. More money is being spent in the defense of Fairbanks alone than was spent in buying all of Alaska in 1867. Naval bases and “listening posts” are being prepared far out in the Aleutian chain. A new Army Air Force cold weather experiment station has been opened to study the special adjustments that are necessary for bomb sights, machine guns, and airplane controls because of the intense cold. It is impossible to build enough heated hangars for the tremendous aerial fleet that is being sent north, so special methods are being developed for warming the engines and thawing out the controls of planes that must be parked out in the weather. The Air Forces were told that it was impossible to do any building during the winter months, but construction of airports and buildings is keeping pace with a fast schedule nevertheless. All building materials except sand, gravel, and lumber have to be imported from the states. Spongy tundra, some of it permanently frozen, is being thawed out and scraped away so that permanent landing surfaces may be laid out. Not only does Alaska guard our northwestern flank, serving as an anchor for the Alaska-Hawaii-Panama triangle, but it insures domination of the entire northeastern Pacific. In laying out the defense facilities there the accent has been on bombers because the present war has indicated that within their areas, land-based bombers can decide the outcome of naval battles. Distances grow short across the top of the world and Dutch Harbor is 2,340 miles from Yokohama, 800 miles closer to Japan than is Hawaii. From another Alaskan base it is a 4,875-mile hop to Hamburg. Panama, the southern corner of the Pacific triangle, was long ago strongly prepared against assault. Now its zone of defense is being extended out into both oceans. Big guns on the hills and in the jungles can outshoot any battleship afloat. Elaborate precautions have been taken to prevent a foreign vessel from scuttling it- self in the canal. Special counter-espionage and anti-sabotage measures are being enforced. Visitors who stray into forbidden areas are presumed to be violating the many “restricted zone” signs and are to be fired upon by hidden guards. The Canal is too important to risk chances. New air bases are under construction on stepping stones to the South Seas, and naval facilities in south Pacific American possessions are being strengthened. America relies on its fleets to keep invaders away and the development of the offshore bases on both coasts have materially increased the ability of our fleets to win their battles. Bases must be handy to possible scenes of action, otherwise the fighting ships might have nearly all their fuel expended when they entered a fight. Ships, bombers, observation and torpedo planes constantly patrol the bases. Likewise, the east and west coasts of the continent itself are under protective surveillance. Naval air and surface vessels are keeping up a continuous security patrol. Closer to the beaches, the smaller craft of the inshore patrols are at work. Today no ship can enter an American harbor without permission and even then it is inspected beforehand.