Question about "handcuff law"

[johnnie]

Does anyone know about the law that says that prisoners can't be handcuffed in front of a jury because it could sway the jury?
I thought it was a federal law, but I'm not sure. Of course I am thinking about this because of the recent Nichols situation. They busted him with two knives a few days before, but yet they were unable to have him handcuffed on Friday, and it didn't turn out too well.
I wonder if this law will be changed.