Answer:
The Supreme Court deemed it important to uphold the faithless elector laws being enacted by some states so that state electors do not go contrary to the intentions of their state's electoral bodies. In addition, the parties elected the electors to vote according to their party loyalties and not according to their individual preferences.
In simple terms, the Twelfth Amendment of the Constitution was not drafted to favor individual prejudices. Electors were specifically required to back their parties when casting their electoral college votes so that they could vote in line with their state's popular votes.
The consequences of allowing electors to vote differently than for the presidential candidate they were pledged to support are:
a) Electors risk using their state's mandate in favor of their personal prejudices.
b) Electors will become disloyal to the parties that elected/selected them as electors.
c) Electors may favor candidates that did not win their state's popular votes, thereby denying the people their right to have their votes counting.
Explanation:
The faithless elector laws being enacted by the states are one of the safeguards to ensure that electors vote for the candidates that win the popular votes in their respective states.