All the times in U.S. history that members of the electoral college voted their own way

Samuel Miles of Pennsylvania had the distinction of being the first, in 1796. Miles was a Federalist who had promised to vote for the Federalist candidate, John Adams, but instead cast his vote for Democratic-Republican candidate Thomas Jefferson.

There have been a total of 157 faithless voters to date, according to FairVote.org, a nonprofit that advocates for national popular-vote elections for president.

Several of them broke with the electorate less out of rebellion than for practical reasons. Throughout the years, 71 electors have changed their votes because the candidate their state chose died before the electoral college could convene. In 1872, for example, Horace Greeley, the nominee of both the Democratic and Liberal Republican parties, lost the general election and died 24 days later . Sixty-three of the 66 Democratic electors refused to vote for a deceased candidate.

The Constitution does not specifically require electors to cast their votes according to the popular vote in their states, but the laws of 29 states and the District of Columbia bind electors to do so. Some require pledges or threaten fines or criminal action, according to a summary of state laws by the National Assn. of Secretaries of State.

No elector has ever been prosecuted for not voting as pledged.

Since 1900, there have been only nine faithless electors who defected for individual reasons, including one who abstained from voting altogether. Here’s a rundown of who they were and why they did it:

Preston Parks of Tennessee was chosen as an elector for the Democratic Party, which was pledged to incumbent Harry S. Truman. Before the election, some Democrats opposed to Truman’s support of civil rights and racial integration split off and formed the States’ Rights Democratic Party, also known as the Dixiecrats. Parks actively campaigned for Dixiecrat candidate Strom Thurmond and said in advance of the election that he would not vote for Truman under any circumstances​​​​​, instead ​voting for Thurmond.  ...