Is Italy safe for American tourists?

Very. Violent crime is rare and far below US levels, and walking through an Italian city at night is generally comfortable, including for women alone in central areas. What exists is petty theft: pickpocketing on crowded transport and around major monuments, bag-snatching from café chairs, and distraction scams. Ordinary precautions cover it — front pockets, a bag that closes and stays in front of you in crowds, nothing valuable left on a restaurant chair. The other real risks are heat in summer and traffic: crossing an Italian street requires more commitment than you're used to.