Did Nationalism have a positive or negative effect on
Italy? Why

Nationalism became the most significant force for self-determination and unification in Europe of the 1800's. ... Nationalist began to form secret societies throughout Italy. Unification was the goal of groups such as the Young Italy Movement led by Giuseppe Mazzini who called for the establishment of a republic.

So in anyone eyes it could be different and also depending on the time period too

congress was not thoroughly prohibiting states from funding religious schools.

d. direct