Axis troops had begun to arrive in Tunisia as early as Nov. 9, 1942, and were reinforced in the following fortnight until they numbered about 20,000 combat troops (which were subsequently heavily reinforced by air). Thus, when the British general Kenneth Anderson, designated to command the invasion of Tunisia from the west with the Allied 1st Army, started his offensive on November 25, the defense was unexpectedly strong. By December 5 the 1st Army’s advance was checked a dozen miles from Tunis and from Bizerte. Further reinforcements enabled Colonel General Jürgen von Arnim, who assumed the command in chief of the Axis defense in Tunisia on December 9, to expand his two bridgeheads in Tunisia until they were merged into one. Germany and Italy had won the race for Tunis but were henceforth to succumb to the lure of retaining their prize regardless of the greater need of conserving their strength for the defense of Europe.

After Rommel had fallen back from Libya to the Mareth Line in mid-January 1943 (see above Montgomery’s Battle of el-Alamein and Rommel’s retreat, 1942–43), two German armies, Arnim’s and Rommel’s, were holding the north and the south of the eastern littoral both against Anderson’s 1st Army attacking from the west and against Montgomery’s 8th from the southeast. Rommel judged that a counterstroke should be delivered first against the Allies in the west. Accordingly, on February 14 the Axis forces delivered a major attack against U.S. forces between the Fāʾiḍ Pass in the north and Gafsa in the south. West of Fāʾiḍ, the 21st Panzer Division, under General Heinz Ziegler, destroyed 100 U.S. tanks and drove the Americans back 50 miles. In the Kasserine Pass, however, the Allies put up some stiffer opposition.

When on February 19 Rommel received authority to continue his attack, he was ordered to advance not against Tébessa but northward from Kasserine against Thala—where, in fact, Alexander was expecting him. Having overcome the stubborn U.S. resistance in the Kasserine Pass on February 20, the Germans entered Thala the next day, only to be expelled a few hours later by Alexander’s reserve troops. His chance having been forfeited, Rommel began a gradual withdrawal on February 22.

The delays ensuing from the frustration of Rommel’s stroke against the 1st Army reduced the effectiveness of his stroke against the 8th. Whereas on Feb. 26, 1943, Montgomery had had only one division facing the Mareth Line, he quadrupled his strength in the following week, massing 400 tanks and 500 antitank guns. Rommel’s attack, on March 6, was brought to an early halt, and 50 German tanks were lost. A sick man and a disappointed soldier, Rommel relinquished his command.

The Allied 1st Army resumed the offensive on March 17, with attacks by the U.S. II Corps, under General George Patton, on the roads through the mountains, with the aim of cutting the Afrika Korps’ line of retreat up the coast to Tunis; but these attacks were checked by the Germans in the passes. In the night of March 20–21, however, the British 8th Army launched a frontal assault on the Mareth Line, combined with an outflanking movement by the New Zealand Corps toward el-Hamma (al-Ḥāmmah) in the Germans’ rear; and a few days later, seeing the frontal assault to have failed, Montgomery switched the main weight of his attack to the flank. Threatened with encirclement, the Germans decided to abandon the Mareth Line, which the 8th Army occupied on March 28; but the German defenses at el-Hamma held out long enough to enable the rest of the Afrika Korps to retreat without much loss to a new line on the Wādī al-ʿAkārīt, north of Gabès. The new line, however, was breached by the 8th Army on April 6; and, meanwhile, the Americans were also advancing on the Axis troops’ rear from Gafsa. By the following morning the Afrika Korps was retreating rapidly northward along the littoral toward Tunis, and by April 11 it had joined hands with Arnim’s forces for the defense of a 100-mile perimeter stretching around Tunis and Bizerte (Banzart).

Thanks to the rapidity of the Afrika Korps’ retreat from Wādī al-ʿAkārīt, the German high command had an opportunity to withdraw its forces from the rump of Tunisia to Sicily, but it chose instead to defend the indefensible rump. The defenders indeed withstood the converging assaults that the 8th and 1st armies delivered against the perimeter from April 20 to April 23; but on May 6 a concentrated attack by Allied artillery, aircraft, infantry, and tanks was launched on the two-mile front of the Medjerda (Majardah) Valley leading to Tunis; and on May 7 the city fell to the leading British armoured forces, while the Americans and the French almost simultaneously captured Bizerte. At the same time, the Germans’ line of retreat into the Cap Bon Peninsula was severed by an armoured division’s swift turn southeastward from Tunis. A general collapse of the German resistance followed, the Allies taking more than 250,000 prisoners, including 125,000 German troops and Arnim himself. North Africa had been cleared of Axis forces and was now completely in Allied hands. Its capture insured the safety of Allied shipping and naval movements throughout the Mediterranean, and North Africa would serve as a base for future Allied operations against Italy itself.

The Atlantic, the Mediterranean, and the North Sea, 1942–45

The year 1942 was, on the whole, a favourable one for the German U-boats. First, the U.S. entry into the war entitled them to infest the U.S. coast of the North Atlantic; and it was not until the middle of the year that the Allies’ introduction of the convoy system from the Caribbean northward constrained the raiders to go so far afield as the waters between Brazil and West Africa. Second, U-tankers were developed; i.e., large converted U-boats equipped to provide fuel, torpedoes, and other supplies to U-boats operating in remote waters. In the course of 1942, the U-boats sank more than 6,266,000 tons of shipping; and, since in the same period their operational strength rose from 91 to 212, it seemed conceivable that they might soon score their desired target of 800,000 tons of sinkings per month.

March 1943 saw the climax of the U-boats’ good fortune: their strength rose to 240; they sank in that single month 627,377 tons of shipping; and, in the greatest convoy battle of the war, when 20 of them attacked two convoys merged into one, they sank 21 ships (141,000 tons) out of 77 with the loss of only one of their own number. The anticlimax followed, thanks to five developments of the Allies’ counteraction: “support groups” were reintroduced; aircraft carriers became progressively available for escorts; more and more long-range Liberator aircraft began to cover the convoys offshore; ships were equipped with a radar set of very short wavelength, the probing of which was undetectable to the U-boats; and a regular offensive against U-boats on their transit routes was launched from the air (56 were destroyed in April–May 1943). The U-boats sank 327,943 tons in April, 264,852 in May, only 95,753 in June 1943; and for the rest of the war monthly totals were less than 100,000 tons except in July and September 1943 and in March 1944.

Late in 1944 the U-boats were equipped with the snorkel breathing tube, which provided them with the necessary oxygen to recharge their batteries under water and so converted them from submersible torpedo boats into almost complete submarines virtually undetectable to radar. About the same time a new model of U-boat, with greater underwater speed and endurance, came into operation. These improvements came too late, however, because the Allies’ surface and air resources for the protection of the convoys were already overwhelming.