Since everyone is pointing out that he actually resides in Brazil most of the time: that is not by choice, but because the U.S. won't permit his significant other to enter the country. His reporting focus is always the US. He was a US constitutional lawyer before becoming a journalist.
hahaha you're such a PRO! Leaving aside the fact he's "based" in Brazil, I predict he'll sign on at a USA paper or broadcaster the very moment such become willing to give him the same editorial freedom to report on USA legal issues he now enjoys at The Guardian: i.e., that will never happen.