Donald Trump has said multiple times that he is worried that November's election will be rigged. Apparently a majority of Republicans agree.

According to a new Gallup poll, 52 percent of Republicans say voter fraud is a major problem in 2016. Despite little evidence that voter fraud has played a significant role in any recent presidential elections or primaries, a whole lot of people believe it poses a threat to the validity of this year's election cycle. Perhaps that has something to do with the comments of many prominent conservatives, including the GOP presidential nominee.

52 percent of Republicans said they are concerned about votes being cast by people who are not eligible vote, compared with 33 percent of independents and just 26 percent of Democrats. Overall, the Gallup found that a third of likely voters think voter fraud is a major issue — Gallup surveyed 1,013 adults nationwide from Aug. 15 to Aug. 16 with a margin of error of plus or minus 4 points.

There is no proof that voter fraud is a significant problem in U.S. elections. In fact, multiple government investigations and independent studies in recent years have determined that the amount of confirmed voter fraud cases in the U.S. to be negligible. But many Republicans remain skeptical that elections are primed to be rigged. The fear has led to the proposal or passing of voter ID laws and other voting regulations in dozens of states across the country.

Meanwhile, those on the left argue that efforts to curb voter fraud is really a veiled attempt to disenfranchise voters, especially low income voters of color, to shift voter demographics in the GOP's favor. Critics allege that voter ID laws, which can make it significantly more complicated for some people, especially non-driver's who do not have a driver's license or other form of photo ID, to vote, are unconstitutional. Monday's Gallup poll found that 40 percent of Democrats think the voter disenfranchisement as a result of such laws is a major problem in 2016, an indication of the polarization present over the issue.

Voter fraud has been increasingly in the headlines lately with Donald Trump stoking fears about a rigged election.

"We'd better be careful, because that election is going to be rigged," the GOP nominee said at an Aug. 1 rally in Columbus, Ohio. "People are going to walk in and they're going to vote 10 times, maybe. Who knows?"

In Trump's estimation, Hillary Clinton rigged the Democratic primary races to gain an edge of her opponent, Vermont Sen. Bernie Sanders, and she plans to do the same in the general election. However, while a recent email leak from the Democratic National Committee revealed evidence of favoritism among Democratic party officials, no evidence has surfaced of significant, intentional voter fraud on behalf of Clinton at the polls.