Donald Trump has been blatant this week about how he thinks the election is "rigged" against him.

At campaign events and on Twitter, the Republican presidential candidate has repeatedly warned against widespread voter fraud and media collusion. Trump says it's all part of a vast conspiracy to get his opponent, Hillary Clinton, elected.

There is no evidence of these claims being true, however. The Associated Press cites a Loyola Law School study that found that out of one billion votes cast in all American elections between 2000 and 2014, there were only 31 known cases of impersonation fraud.

But Trump is urging his supporters to watch the polls anyway.

"They even want to try to rig the election at the polling booths, and believe me, there's a lot going on," he said at a rally in Green Bay, Wisconsin on Monday.

Trump is advocating for poll watchers to keep an eye out for voter fraud on election day.

In Idaho, poll watchers can legally be at polling places throughout the state.

"Traditionally it's a get out the vote effort," said Phil McGrane with the Ada County Clerk's Office. "Obviously the conversation this year is a bit different, it has less to do with get out the vote and more to do with watching the process."

While watchers are able to be at the polls and witness that process, there are still rules that they must abide by.

"No one off the street can just walk in and say I want to be a poll watcher," said Idaho Secretary of State Lawrence Denney. "Certainly we would hope that people would understand that you can't just show up in mass to be poll watchers without being registered first."

"It has to come through a political party or a candidate," said McGrane. "Each candidate or political party is entitled to one watcher at any precinct."

After the campaign or political party vets and chooses poll watchers, the list of poll watchers goes to the clerk's office.

"We'll certify those names and there will be specific locations those watchers are able to observe and then those people are allowed to see the process."

To make sure everyone is on the same page, poll workers are told in advance who the poll watchers are for a given location. Once voting starts there are rules for what poll watchers are and are not allowed to do, including where they are allowed to stand.

"We typically ask poll watchers to stay near the receiving clerk," said McGrane. "It also puts them in a space that's not going to interfere with someone voting. We don't want someone to look over someone's shoulder, see how they're voting or someone to get in the way of the process and disrupt it for another voter."