The results of the June 1946 referendum on whether or not Italy should remain a monarchy or become a republic led to a result in favor of a republic, albeit not by such a large margin. The pro-republican side won the vote with 54.3% of the vote, while the pro-monarchy side lost with 45.7% of the vote. The divide was quite simple, the South of Italy primarily voting for the monarchy and the North of Italy voting for a republic. This vote was not close by any means, but it was not a blowout either.
My challenge is for the monarchy to not only survive this referendum, but to last until the modern day. The earliest point of divergence must be after Italy enters the war on the side of Germany, and the latest being the referendum itself. How do you think Italy could retain the monarchy? Is it plausible for King Umberto II to remain in his office? And, although this does go past the boundaries of the challenge, is it plausible for a restoration to take place at some point in the future after a referendum in favor of a republic?