Darth Cheney arrests his critics -- surprised?

You can read here about how a man who dared criticize Vice President Cheney -- to his face! -- regarding the Iraq War was immediately arrested by the Secret Service, who wanted to charge him with harassment. (Hat tip: Andew Sullivan) Luckily, the man was released w/out charge, and now he's suing the Secret Service agent that arrested him.

Why not sue Cheney too?