I can't see why it wouldn't be. It's a purely executive branch thing.
It's almost certainly unethical, and an invitation to crime. But I doubt the Supreme Court will find it a crime in itself. They'll say that it's up to the legislature to fix it.
The suit will cite the Civil Service Reform Act, the Whistleblower Protection Act, the Hatch Act, and the Uniformed Services Employment and Reemployment Rights Act as the legislature's attempt to fix it, but since they weren't extremely specific about this particular job, Congress will just have to have another go at it. And I'm sure they'll get right on that.
