If the delegates decide to play the “conscience clause” card, do they need to declare a reason? They’d be conscientious objectors, but on what grounds? And would this set a new precedent for the average joe in his own future decisions? The “conscience clause” is a two edged sword.
It’s not a conscience clause. It’s just how it works. Delegates are only bound to a candidate insofar as they accept the mutual agreement between the states and national party. If they reject that agreement by adopting different rules to govern the convention, they are not bound. They set the rules not the states or the national party apparatus.
It doesn’t matter if a state has passed laws to bind delegates. Those laws are unenforceable by the federal government or the national party. If a state passes a law mandating that a delegate be prosecuted for not voting according to how (s)he is bound, then the state can enforce that law after the vote takes place but it cannot intervene to prevent a delegate from voting however (s)he wants at the national convention.
A political party is a private party not an administrative agency of the government.