At least one Republican elector in Wisconsin is being inundated with requests to change his vote for Republican Donald Trump when the Electoral College meets Monday, Dec. 19.

Brian Westrate, the elector for Wisconsin's 3rd Congressional District, said the email requests started slowly but picked up substantially toward the end of last week.

"Now I probably am getting 100 an hour," Westrate said, "and the vast majority of them are form letters, you know, 'contactyourelector.com' or something where you put in your name, your city and then press send. ...I was originally replying to them all, but now the sheer volume has made it so I can't delete them fast enough."

Westrate said many of the messages are asking him to change his vote because of Democrat Hillary Clinton's lead in the popular vote. But what matters is Trump won Wisconsin, he said.

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"People who are messaging me asking me to change my electoral vote are asking me to change the rules of the game after the game has been played," he said.

This isn't the first time electors have been pressured in Wisconsin. Democrat Christine Bremer-Muggli cast an electoral vote for President Barack Obama in 2008.

"In 2008, I received many letters asking me not to vote for Barack Obama because they 'knew' he was not an American and he was born in Kenya," Bremer-Muggli said.

Each state gets one elector for each congressional district, plus two for its senators. Instances of electors not supporting the choice of their state are very rare.