Dozens of leaders, mostly from Western states, have asked the Supreme Court to overturn lower court decisions that restrict enforcement against public camping.
The story of Newsom going to the Supreme Court is because they need to bypass that ruling if they want to be able to move people out who are refusing offers of shelter.
There was a recent court ruling that prevented SF from being able to practically touch any sidewalk encampment: https://apnews.com/article/lawsuits-oakland-9685f0a4350f8eb45602417ad334006f
The story of Newsom going to the Supreme Court is because they need to bypass that ruling if they want to be able to move people out who are refusing offers of shelter.