The U.S. Court of Appeals for the 10th Circuit in Denver ruled on August 20, “states do not have the constitutional authority to interfere with presidential electors who exercise their constitutional right to vote for the President and Vice President candidates of their choice" (page 93 of decision). The court decision resulted from a lawsuit filed after 3 Democratic presidential electors from Colorado refused to vote for Hillary Clinton when the Electoral College met on December 19, 2016.
This court decision was not about the National Popular Vote Compact. Whether this decision is upheld or reversed by the U.S. Supreme Court, this decision would not affect the operation of the National Popular Vote interstate compact, because the compact does not rely on the state laws that purport to require presidential electors to vote a certain way. The compact does not try to tell presidential electors to vote a certain way.
The decision (if upheld after appeal to the U.S. Supreme Court) would negate existing laws in all 26 states (such as Colorado) that purport to require presidential electors to vote for their party’s nominee for President.
However, the remaining 24 states do not have, and never have had, laws purporting to tell presidential electors how to vote.
In fact, the National Popular Vote Compact would operate in a manner identical to the system that has been used for over 200 years in the 24 or so states that do not have laws requiring presidential electors to vote a certain way. In these 24 states (which currently use the state-by-state winner-take-all method of awarding electoral votes), the presidential electors are the persons nominated by the political party whose presidential candidate receives the most popular votes inside the state. The National Popular Vote Compact would operate in same way, except the presidential electors would be the persons nominated by the political party whose presidential candidate receives the most popular votes in all 50 states and the District of Columbia.
That is, both the current system and the National Popular Vote system rely on the political parties to vet and select their presidential electors. This system has worked very reliably over the years in the 24 states that do not purpose to tell their presidential electors how to vote. And, it has worked very reliably in the 26 states that have adopted laws (all after the 1960s) that purport to tell presidential electors how to vote. After 23,529 electoral votes in 58 presidential elections between 1789 and 2016, the vote of Samuel Miles in 1796 was the only case when an electoral vote was cast in an unfaithful way by a presidential elector who might have thought, at the time he voted, that his vote might affect the outcome. See section 2.12 of Every Vote Equal book at www.Every-Vote.Equal.com
During the same period (1789 to 2016), there has been 16 "grand-standing" presidential electors -- that is, electors who have cast a deviant vote for President knowing, at the time they voted, that their vote would not affect the outcome of the election in the Electoral College. However, until 2016, there never more than one in a given election. Having 7 faithless presidential electors in one year (2016) was unusual.
Given the amount of publicity received by the 7 grandstanding faithless electors in 2016, both parties can be expected to be extremely careful in 2020 about vetting the people they nominate for the position of presidential elector. If the political parties do their job of vetting their nominees for the position of presidential electors, faithless electors cannot have any effect on the outcome -- under either the current system or the National Popular Vote compact.
In any case, the 10th Circuit decision is likely to be reviewed by the U.S. Supreme Court because the Washington State Supreme Court reached the opposite conclusion concerning faithless electors.
It remains to be seen whether the U.S. Supreme Court will hear and whether it will uphold the 10th Circuit decision. As the 10th Circuit decision itself noted on page 67, “The Supreme Court, however, has considered a closely analogous question -- whether a primary candidate for party elector can be required to pledge to support the party’s candidate.” The Supreme Court concluded in that case that the state could require the pledge.
If there is any remaining concern, states that currently have laws purporting to require presidential electors to vote a certain way could enact Pennsylvania’s law in which the presidential candidate directly chooses the people to serve as his or her presidential electors (25 P.S. §2878).
The National Popular Vote organization is not planning to offer a brief on either side of this issue if the U.S. Supreme Court decides to hear the appeal from the 10th Circuit, because the 10th Circuit decision does not affect the operation of the National Popular Vote interstate compact.