Donald Trump has doubled down on his accusations of voter fraud and a "rigged election."

At a rally yesterday in Wisconsin, the GOP candidate said, "They even want to try to rig the election at the polling booths. And believe me, there's a lot going on." He continued, "So many cities are corrupt, and voter fraud is very, very common."

Fact checkers disagree. PolitiFact gave Trump a "pants on fire" rating for his claims of large scale voter fraud, saying the charges do not reflect reality. PolitiFact cites Justin Levitt, a professor at Loyola Law school and an expert on voter fraud, who found only 31 credible incidents out of more than 1 billion votes cast between 2000 and 2014.

Still, we think this is a good time to learn the straight truth about exactly how vote counting works in Massachusetts. We turned to the secretary of the commonwealth, who oversees the state's elections, for answers.

Guest

William Galvin, secretary of the commonwealth of Massachusetts.