Answer:
Yes. It is illegal.
Step-by-step explanation:
Even though it's hard to prove, the act of gerrymandering is considered illegal.
This is evident in the case of Miller v. Johnson in 1995 where the Supreme Court ruled that the act of racial gerrymandering is unconstitutional.
On the other hand, the act of partisan gerrymandering has always been difficult to prove.
Therefore, the act of gerrymandering is difficult to establish, it is however considered illegal.