The Statuto Albertino is a decision unique to Sardinia-Piedmont. It cannot be taken once Italy is formed. The decision is an introduction of a constitution, but unlike the similar Liberian decision Constitution for Liberia it doesn't actually change any reforms.
It requires only that the average militancy is above 3. Then militancy will be reduced by 2 and Sardinia-Piedmont will get 5 prestige.
The ingame text: The Albertine Statute was a constitution enacted by the Kingdom of Sardinia-Piedmont, in response to concerning revolutionary activity in the country, on the 4th of march 1848. The Statute formalized the absolute monarchy of Sardinia-Piedmont, and would later be used, although in modified forms, as the basis of the Italian constitution all the way up to 1948