Plenty of departments in other countries do routinely carry guns, including in Italy, Spain, France and Germany. The first time I ever saw a submachine gun was at a train station in Germany, it was shocking to see cops walking around as routine so heavily armed like it was no big deal, despite an obvious lack of threat anywhere.

You have to solve both sides of the gun equation for a disarm to work in the US, because violent criminals have very easy access to guns here. If you remove guns from the cops without doing so on the otherside, you're going to unleash hell.