WHEN Allied forces liberated Italy after 540 days of intense fighting, Winston Churchill was elated. ''There have been few campaigns with a finer culmination,'' he wrote later.
His satisfaction was more than justified. The war for Italy was supposed to be a sideshow, a holding action to draw off 1 million Nazi troops while Russian Armies drove West and Allied commanders finalized plans for the great invasion of France.
Instead, the polyglot Allied force sent to Italy in the summer of 1943 succeeded in knocking Hitler's main European ally out of the war, seizing Rome, and -- 50 years ago tomorrow -- defeating the powerful German Army assigned to hold the peninsula.
At Cassino and Anzio, where the fighting was hardest, ''some of the most incredible testimonies to the bravery of the Allies in World War II'' were recorded, according to another military historian.
''The fighting in Italy was epic by any standard,'' says Col. Peter Herrly, a National War College professor.
The Allied campaign in Italy -- the longest of World War II -- was the product of an uneasy compromise between the leaders of the Allied war effort, Churchill and President Franklin Roosevelt.
Roosevelt's military advisers wanted to concentrate on preparations for a full-scale invasion of Nazi-occupied France. Churchill, haunted by memories of the devastating trench warfare of World War I, wanted to attack Germany at weaker points, starting in North Africa.
In the end, the two wartime leaders agreed to attempt both, a decision that may have delayed the invasion of France for a year.
''The key issue at stake was whether the Allies would cross [into France] in '43 or '44,'' says John Mearsheimer, a political scientist at the University of Chicago.
After North Africa was cleared of Axis forces in May 1943, a reluctant Roosevelt agreed to carry the war into Italy.
Allied forces struck first at Sicily in July in an amphibious landing that was surpassed in size only by the invasion at Normandy, France, a year later. The shock waves were felt in Rome, where the regime of Italy's Fascist dictator, Benito Mussolini, was overthrown and replaced by a government that promptly declared war on Germany.
After driving German forces off of Sicily, Allied troops, in September, began a long, costly march up the mountainous Italian peninsula.
The Allies encountered fierce German resistance, notably at Cassino in central Italy, but also on the beaches of Anzio, where an amphibious force struggled for four months to secure a foothold south of Rome. In June 1944, Rome was taken, the first time in history from the south.
The Allies finally broke through German defenses in June 1944 and captured Rome just two days before the D-Day invasion of France.
German troops held fast in northern Italy through the fall and winter. But in the spring, Allied forces advanced toward the Alps. On May 2, two days after Hitler committed suicide in Berlin, the German Army in Italy finally surrendered.
As for the man who dominated Italy for two decades, the end was also at hand. After being overthrown, Mussolini was rescued by German paratroopers and taken to northern Italy to establish a puppet regime, a fig leaf to legitimize the German military presence on the Italian peninsula.
But on April 28, 1945, he and his mistress were captured by Italian resistance forces. Two days later, they were shot and their bodies hung in a public square in Milan.
Since the war, historians have raised questions about the Italian campaign. As a secondary theater, it was starved of resources, which were being husbanded for the invasion of France. Because Allied commanders opted for a frontal assault against German infantry positions, moreover, the value of United States air and naval power was marginalized.
A few historians even fault the decision to invade Sicily, arguing that seizing Sardinia first would have made it possible for the Allies to outflank German troops in northern Italy.
''By going into Sicily instead of Sardinia, we may have prolonged the war in Italy for a year,'' says Samuel Mitcham, author of several books on the war in Italy and North Africa, and a professor in the geography department at Southeast Louisiana University in Monroe, La.
But in the end, nearly all historians agree, Germany suffered more from the diversion of resources required by both sides to contest Italy.
''The bottom line is that the trade-off worked to the Allies' advantage,'' says Martin Blumenson, who has also written several books on World War II.
Ironically, Mussolini himself made largely unnoticed contributions to both the beginning and end of World War II.
The failure of the Western democracies to resist his aggression in Ethiopia in 1935 helped convince Hitler that he could pursue German ambitions in Europe with impunity, setting the stage for World War II.
Mussolini's ill-fated 1940 invasion of Greece, meanwhile, may have contributed to Hitler's ultimate defeat.
After Italian troops were driven back into Albania, Hitler -- who was also distracted by events in Yugoslavia -- was forced to dispatch forces to shore up the Balkans.
The diversion delayed the start of Germany's massive assault on the Soviet Union for several weeks -- weeks that were crucial to gaining victory on the Eastern Front before the onset of the Russian winter of 1942-43.