It wasn't chlorine or acetylcholinesterase inhibitor. It was acute fluoride toxicity, in this case probably hydrogen fluoride. (No name delivered "smiles" to Syria.)
They can deliver fluoride overdoses in the U.S. by hacking water fluoridation systems that use sodium fluoride.
Scooter Libby was set up by a U.S. attorney who went grand jury shopping. He should never have been prosecuted; he should have been pardoned. Bush didn't have the balls to pardon his friend even though he and everyone else knew it would be the right thing to do; Trump pardoned him on principle, with no personal connection at all.