A quote from an Innertube video, summarizing the early United States reaction to the situation in Italy. The collapse of the German backed Italian Social Republic was in fact a disaster for both the Germans and the Western Allies: the Soviets rushed to provide aid to the Italians, smashing through German defenses in Austria and working with the Yugoslavian partisans to do so. The underground Italian Communist movement managed to seize control of the revolts, and the northern portion of the country. Rome was handed over to South Italy, but the countryside would fall under control of the communists and Rome became an exclave of the Republic of Italy, while the newly established Socialist Republic of Italy was headquartered in Florence.
The Italians were a little more distant from the Soviets, at least compared to their former axis-partners in the German Democratic Republic; with the Soviets having made it to the Rhine, the Germans were kept on a very, very short leash by Stalin. The Italians, by contrast, were actually closer with the Yugoslavs, Austrians, and Bulgarians in forming a quiet miniature alliance under the larger Soviet umbrella. The Italians were genuinely democratic and managed to resurrect industry in the area, becoming an economic powerhouse all their own (though certain leftist thinkers would decry their methods as downright capitalistic).
By contrast, the Republic of Italy (official capital at Rome, in reality it was in Naples) was a bit of a disaster. Though the south had been little damaged in the war, they were hopelessly corrupt: more than any other country, United States reconstruction funds were often embezzled, and Fascists escaped justice more than anywhere else. The connections to the Mafia families only expanded after the war, with South Italy becoming more and more of a haven for crime in the Med. The expected brain drain from the North that may have bolstered the South's fortunes did not come to pass, many intellectuals simply moving on the US or Australia.
This entirely was exposed in 1962, when the assassination of the President's brother and Attorney General, Robert F. Kennedy, was carried out on the orders of a prominent Mafioso for daring to pursue their organization in New York. When the rifle that carried out the hit was revealed to have come from a South Italian armory, it was exposed that South Italy had been running guns, drugs, and other contraband back and forth across the Atlantic.
America essentially intervened in the South Italian crime situation, though officially only there to support the local police, and essentially occupied the country for the rest of John F. Kennedy's presidency. Meanwhile, North Italy quietly prospered, becoming one of the richest countries in Europe and with some of the most productive factories. The fact that many South Italians were actually crossing the border to the north was immensely embarrassing for the West.
"Turns out, cowboys make pretty good communists!"