Fact, they are not voters. They are the representative of voters, They have no say in it since they are representing the people who sent them there not themselves. This is the same argument our current crop of so called Conservatives uses in DC. Promise to represent the people then do what they hell they want. Either they are representatives or they are nothing.
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https://ballotpedia.org/Verbatim_fact_check:_Would_it_be_%22totally_illegal%22_for_delegates_pledged_to_Donald_Trump_to_vote_for_another_candidate_at_the_Republican_National_Convention%3FThis link provides
"Election laws relating to delegates by state (click "show" to open)""It's also not clear if any of those state laws are constitutional. While the U.S. Supreme Court has never ruled on how delegates may vote at a political party’s national convention, it has ruled on whether a state’s laws can supersede a party’s convention rules.
In Cousins v. Wagoda (1975), the Supreme Court ruled on whether a circuit court was “correct in according primacy to state law over the [Democratic] Party’s rules in the determination of the qualifications and eligibility of delegates to the Party’s National Convention.”[5] In an 8-1 decision, the justices held that the lower court had been incorrect. In the majority opinion, Justice William Brennan wrote,
“The States themselves have no constitutionally mandated role in the great task of the selection of Presidential and Vice-Presidential candidates. If the qualifications and eligibility of delegates to National Political Party Conventions were left to state law ‘each of the fifty states could establish the qualifications of its delegates to the various party conventions without regard to party policy, an obviously intolerable result.’ Such a regime could seriously undercut or indeed destroy the effectiveness of the National Party Convention as a concerted enterprise engaged in the vital process of choosing Presidential and Vice-Presidential candidates— a process which usually involves coalitions cutting across state lines. [Internal references omitted.][2] ”
[5]
Six years later in Democratic Party of U.S. v. Wisconsin ex rel. La Follette, the court ruled a Wisconsin state law did not supersede the rules established by the Democratic Party in the matter of choosing which delegate to admit to its national convention. Writing for the majority, Justice Potter Stewart stated, “This First Amendment freedom to gather in association for the purpose of advancing shared beliefs is protected by the Fourteenth Amendment from infringement by any State.”[6]
I seem to recall that this was well known before the 70's. We were taught in school that even though a delegate was "bound" by the state that they could vote their conscience. (of course that is relying on a very old memory!!)