Colorado was the first state to void an elector's faithless vote, which occurred during the 2016 election. Minnesota also invoked this law for the first time in 2016 when an elector pledged to Hillary Clinton attempted to vote for Bernie Sanders instead. Until 2008, Minnesota's electors cast secret ballots. Although the final count would reveal the occurrence of faithless votes, it was impossible to determine which electors were faithless. After an unknown elector was faithless in 2004, Minnesota amended its law to require public balloting of the electors' votes and invalidate any vote cast for someone other than the candidate to whom the elector was pledged.