Republican Elector Will Not Cast Vote For Trump

This is right IMO:

Since the election, people have asked me to change my vote based on policy disagreements with Donald J. Trump. In some cases, they cite the popular vote difference. I do not think president-elects should be disqualified for policy disagreements. I do not think they should be disqualified because they won the Electoral College instead of the popular vote. However, now I am asked to cast a vote on Dec. 19 for someone who shows daily he is not qualified for the office.

This is also reasonable, though it's a tougher call since you could argue that our understanding of the EC has changed:

The United States was set up as a republic. Alexander Hamilton provided a blueprint for states’ votes. Federalist 68 argued that an Electoral College should determine if candidates are qualified, not engaged in demagogy, and independent from foreign influence. Mr. Trump shows us again and again that he does not meet these standards. Given his own public statements, it isn’t clear how the Electoral College can ignore these issues, and so it should reject him.