Except that in the common law system of the United States, a judge can throw out the regulation.
That's very much not the difference between common and civil law
If the law is constitutional it can't be thrown out by a judge in common law and if it's not it can be declared so in civil law
The difference between the two is more about what happens in the absence of a law
To be fair to Italy, this happens everywhere quite frequently. In my country (the US) we do this all too often.