Your thinking on contract law, democratic representation, and the duty of a delegate to represent the best interest of his countrymen is completely confused.
delegates are proxies and bound to vote the way they have been directed to vote.
You’re not proving your point.
Where do you get your definition of “duty?” What about the duty of an adult not to enter into contracts they don’t believe in or intend to keep?
If an adult does enter into an agreement or signs a contract/affidavit/or pledge and then claims he didn’t mean it, he’s not trustworthy. He’s not someone who knows his own mind, much less the “best interest of others.0