system
Given the following post, respond as if you're commenting on Reddit:
human
[Harry Potter] Why was a murdered man's alma mater designated as who decided where his kid should go? What authority did Dumbledore have to take baby Harry from an active crime scene?
gpt
Dumbledore wasn't just a headmaster, he was also  Supreme Mugwump of the International Confederation of Wizards (basically equivalent to the Secretary-General of the UN) and Chief Warlock of the Wizengamot (basically the head of the highest court of wizarding law).  In other words, Dumbledore did have quite a lot of legal authority.  

More importantly, though, was Dumbledore's role as the leader of the fight against Voldemort, analogous to a general fighting against an enemy army.  James and Lily Potter were killed by Voldemort, so Dumbledore stepped in to decide and oversee what would be done next.  

Plus... he's *Dumbledore*.  Who's gonna tell him he's not allowed to do something?