May 10, 2016 - On Tuesday voters in West Virginia head to the polls for that state's presidential primary. It's a region where coal is king, but that could be changing and many are now wondering just how much the issue of coal will play a role in the 2016 election.

West Virginia Sen. Joe Manchin is standing by Hillary Clinton, despite a comment she made in March which angered many of his constituents.

She said, "We're gonna put a lot of coal miners and coal companies out of business," but has since walked back those comments.

Sen. Joe Manchin (D- W.V.) said last week Clinton is the best candidate to deal with the biggest problems in the state, like extreme poverty and unemployment.

Still,many voters aren't convinced, including many Democrats who say they'll back trump.

"He's for coal mining. Here in Logan county people live on coal mining," said Debbie Thompson, a registered Democrat.

Donald Trump has been firing back at Secretary Clinton, trying to draw a contrast, often telling West Virginia voters, "I'm going to put the miners back to work."

It's a promise some experts say would be difficult to keep given the explosion of natural gas as an energy source in this country, years of additional regulations on coal power plants and President Obama's Clean Power Plan.

"The coal industry in this country is never going to bounce back to where it was most likely and political promises to the country probably can't transform that, said Philip Wallach, a senior fellow with The Brookings Institution who has researched this issue.

Wallach said the issue of coal could play a role in states like West Virginia, Kentucky and the battleground state of Ohio, but likely won't be a top issue in the general election.

"There are these few regions where that's central to people's livelihood and it could be pivotal but overall I think it's likely to take a back seat to what the future of american government looks like," Wallach said.