The United States' Electoral College system is largely based on electors voting for the candidate who won the popular vote in their state. But what happens if electors change their minds at the last minute?
Electors who don't vote for the candidate they've pledged to vote for are called "faithless electors." This designation only applies to pledged electors, not unpledged electors who have not pledged their support to a presidential or vice presidential candidate (however, there haven't been any unpledged electors since the 1964 election). More than 99 percent of electors have followed their pledges while voting, according to the National Archives and Records Administration.
While no federal law or constitutional provision exists to prevent electors from voting for a candidate other than the one chosen by popular vote in their state, many states and the District of Columbia have their own requirements for electors. The constitutionality of state laws surrounding pledged voting was confirmed by the Supreme Court in the 1952 case of Ray v. Blair. Still, no faithless elector has actually ever been prosecuted.
There have only been 157 faithless electors in the Electoral College, and out of this number 71 changed their vote because the original candidate died before Election Day. The most recent incident was in 2004, when an anonymous Democratic elector in Minnesota voted for John Kerry's running mate John Edwards, presumably by accident. In 1836, however, the entire Virginia electoral delegation voted faithlessly against vice presidential candidate Richard Johnson because of Johnson's public interracial relationship with his slave. Still, faithless electors have yet to impact the end result of any presidential election thus far.
Is there a chance of electors changing their minds in this election? Well, in August one elector publicly announced his intention to vote against his party's candidate. Baoky Vu, a businessman from Georgia, was one of Georgia's 16 Republican electors when he put out a statement saying he would not be voting for Donald Trump, The Atlanta Journal-Constitution reported. "I take my role seriously and in the face of the difficult choice before us, I will always put America first over party and labels," Vu wrote.
Georgia does not require its electors to follow the results of the popular vote while casting their ballots, but Trump supporters called Vu "a disgrace," in light of his decision, according to The Atlanta Journal-Constitution. By 5 p.m. EST that day, Vu had resigned as an elector.
So while only one would-be elector has publicly toyed with the possibility of voting faithlessly so far, we'll likely have to wait for Election Day to see if any other elector dares follow in his footsteps.