Romney said his conscience wouldn't let him vote for Trump. Ryan was telling Republicans to "vote their conscience." So were Kasich and numerous editorial writers.
The phrase may have been a negative "dog whistle" for the delegates who took it to mean "Don't vote for Trump."
Reagan's 1976 speech wasn't a ringing endorsement of Gerald Ford, but he did say the party had to stick together, and that was enough. If Ted had put it that way, the reaction would have been weaker and milder.
“The phrase may have been a negative “dog whistle” for the delegates who took it to mean “Don’t vote for Trump.”
That’s how I took it.