Hundreds of billions in support, massively increased defense spending, and hefty sanctions are obviously nothing..

Also much more people have been to Italy,or at least know the country and it's culture compared to Ukraine. So the Fallout in Public Opinion would be way worse. China would also be salivating at an Opportunity to isolate the US, and that would be one presented on a silver platter

Wiping off Italy for no reason is enough to trigger a French nuclear response.