system
Given the following post, respond as if you're commenting on Reddit:
human
[Fantastic Beasts] What about Grindelwald's disguise as Percival Graves?

Lets look at the facts. No one questions the fact that Graves is a powerful wizard, nor bats an eye at displays of wandless magic that border on telekinesis. Also Graves is apparently very high ranking in MACUSA, with the ear and respect of the President.


That leads me to two options:


1) Grindlewald has been impersonating Graves for years, and no one noticed that powerful wizard Graves always seemed to take a holiday whenever there was Grindelwald terrorist activity. 



2) Grindlewald was able to locate, subdue and successfully impersonate a high ranking wizard powerful enough that he wouldn't need to hide his own power overmuch. However, said Grindlewald also needed MACUSA's resources to locate a "squib" child with special powers.
gpt
If Bartemius Crouch Jr, who had been kept wandless and alone for many years under the Imperius curse, managed to subdue Mad-Eye Moody enough to lock him in a trunk and impersonate him for a year using polyjuice potion, the same thing would be a cinch for Grindelwald at his full power.