Example: Let's say one party wants to raise the top tax rate to 98%. Sounds confiscatory!!! But wait!! They also allow a 100% deduction for all earned income. The effective tax rate on a CEO who earns $1.2 million on his W-2 (and has no other income) would be exactly zero.
I can't even find a definition for "nominal tax rate." There are lots of ways to describe tax rates. I don't think "nominal" is one of them.