It's "national service". A concept perhaps alien in the US, but basically most countries have a programme where eighteen-yr olds have to go through service in a government job, either in the army, police, fire or EMT. I mentioned that as the comment above mentioned the IDF.
Police standing around in subways is still a deterrent from bad behavior, especially when coupled with a justice system that doesn't reward criminals. See Japan, Korea, Singapore, Dubai, Israel, etc.
Well, until the cops start actually serving the public rather than being (again) security theatre, I stand by my skepticism. I understand other countries have much less organized-crime-like police cultures.
National service is not a concept that's alien to the US, it's just one that was massively delegitimized by the government sending tens of thousands of young men and women off to die in Asia, for ends many would characterize as "meaningless" or "evil", in hindsight. Abuse and exploitation of patriotism leading to distrust and deflated enthusiasm. (This is a dynamic Israel might want to pay attention to.)
Police standing around in subways is still a deterrent from bad behavior, especially when coupled with a justice system that doesn't reward criminals. See Japan, Korea, Singapore, Dubai, Israel, etc.