To decide what should be done after victory in North Africa, Roosevelt and Churchill, with their advisers, met at Casablanca in mid-January 1943. After long argument, it was eventually agreed that Sicily should be the next Axis area to be taken, in July. For the war against Japan, it was decided that two offensive operations should be undertaken: MacArthur should move toward the Japanese base at Rabaul, on the island of New Britain; and convergent movements on Burma should be made by the British from the mainland of India and by the Americans from the sea. Politically, the Casablanca Conference owes its importance to the fact that, at its end, Roosevelt publicly announced a demand for the unconditional surrender of Germany, Italy, and Japan.

Only four months after Casablanca it became necessary to hold another Anglo-U.S. conference. In mid-May 1943, Roosevelt, Churchill, and their advisers met, in Washington, D.C., for the conference code-named Trident. There the Sicilian project was effectively confirmed, and the date May 1, 1944, was prescribed—definitively in the U.S view, provisionally in the British—for the landing of 29 divisions in France; but the question whether the conquest of Sicily should be followed, as the British proposed, by an invasion of Italy was left unsettled.

The Eastern Front, February–September 1943

The German counteroffensive of February 1943 threw back the Soviet forces that had been advancing toward the Dnepr River on the Izyum sector of the front, and by mid-March the Germans had retaken Kharkov and Belgorod and reestablished a front on the Donets River. Hitler also authorized the German forces to fall back, in March, from their advanced positions facing Moscow to a straighter line in front of Smolensk and Orël. Finally, there was the existence of the large Soviet bulge, or salient, around Kursk, between Orël and Belgorod, which extended for about 150 miles from north to south and protruded 100 miles into the German lines. This salient irresistibly tempted Hitler and Zeitzler into undertaking a new and extremely ambitious offensive instead of remaining content to hold their newly shortened front.

Hitler concentrated all efforts on this offensive without regard to the risk that an unsuccessful attack would leave him without reserves to maintain any subsequent defense of his long front. The Germans’ increasing difficulty in building up their forces with fresh drafts of men and equipment was reflected in the increased delay that year in opening the summer offensive. Three months’ pause followed the close of the winter campaign.

By contrast, the Red Army had improved much since 1942, both in quality and in quantity. The flow of new equipment had greatly increased, as had the number of new divisions, and its numerical superiority over the Germans was now about 4 to 1. Better still, its leadership had improved with experience: generals and junior commanders alike had become more skilled tacticians. That could already be discerned in the summer of 1943, when the Soviets waited to let the Germans lead off and commit themselves deeply to an offensive, and so stood well-poised to exploit the Germans’ loss of balance in lunging.

The German offensive against the Kursk salient was launched on July 5, 1943, and into it Hitler threw 20 infantry divisions and 17 armoured divisions having a total of about 3,000 tanks. But the German tank columns got entangled in the deep minefields that the Soviets had laid, forewarned by the long preparation of the offensive. The Germans advanced only 10–30 miles, and no large bag of Soviet prisoners was taken, since the Red Army had withdrawn their main forces from the salient before the German attack began. After a week of effort the German armoured divisions were seriously reduced by the well-prepared Soviet antitank defenses in the salient. On July 12, as the Germans began to pull out, the Soviets launched a counteroffensive upon the German positions in the salient and met with great success, taking Orël on August 5. By this time the Germans had lost 2,900 tanks and 70,000 men in the Battle of Kursk, which was the largest tank battle in history. The Soviets continued to advance steadily, taking Belgorod and then Kharkov. In September the Soviet advance was accelerated, and by the end of the month the Germans in Ukraine had been driven back to the Dnepr.

The Southwest and South Pacific, June–October 1943

A Pacific military conference held in Washington, D.C., in March 1943 produced a new schedule of operations calling for the development of some counterattacks against the Japanese. The reduction of the threat from the large Japanese naval base at Rabaul, by encirclement if not by the capture of that stronghold, was a primary objective for MacArthur.

Between June 22 and June 30, 1943, two U.S. regiments invaded Woodlark and Kiriwina islands (northeast of the tip of Papua), whence aircraft could range over not only the Coral Sea but also the approaches to Rabaul and to the Solomons. At the same time, U.S. and Australian units advanced from Buna along the coast of New Guinea toward Lae and Salamaua, while other Australian forces simultaneously advanced from Wau in the hinterland; and in the night of June 29–30, U.S. forces secured Nassau Bay as a base for further advances against the same positions.

U.S. landings on New Georgia and on Rendova in the Solomons, however, also made in the night of June 29–30, provoked the Japanese into strong counteraction: between July 5 and July 16, in the battles of Kula Gulf and of Kolombangara, the Allies lost one cruiser and two destroyers and had three more cruisers crippled; and the Japanese, though they lost a cruiser and two destroyers, were able to land considerable reinforcements (from New Britain). Only substantial counter-reinforcement secured the New Georgia group of islands for the Allies, who, moreover, began on August 15 to extend their operation to the island of Vella Lavella also. In the last two months of the struggle, which ended with the Japanese evacuation of Vella Lavella on October 7, the Japanese sank an Allied destroyer and crippled two more but lost a further six of their own; and their attempt to defend the Solomon Islands cost them 10,000 lives, as against the Americans’ 1,150 killed and 4,100 wounded.

Meanwhile, U.S. planes on August 17–18 had attacked Japanese bases at Wewak (on the New Guinea coast far to the west of Lae) and destroyed more than 200 aircraft there. On September 4 an Australian division landed near Lae, and the next day U.S. paratroops dropped at Nadzab, above Lae on the Markham River, where they were soon joined by an Australian airborne division. Salamaua fell to the Allies on September 12, Lae on September 16, and Finschhafen, on the Huon Peninsula behind Lae, on October 2. On Sept. 30, 1943, the Japanese made a new policy decision: a last defense line was to be established from western New Guinea and the Carolines to the Marianas by spring 1944, to be held at all costs, and also to be used as a base for counterattacks.