Democratic presidential candidate Clinton speaks at a Service Employees International Union roundtable on Home Care at Los Angeles Trade-Technical College in Los Angeles Thomson Reuters WASHINGTON (Reuters) - In her 2008 bid for the White House, Hillary Clinton cast herself as a blue-collar Democrat who was unabashedly pro-coal, a stance that helped her beat opponent Barack Obama easily in primaries in states that produced or were reliant on coal.

Eight years later, a Reuters review of her recent campaign speeches and policy announcements shows that the great-granddaughter of a Welsh coal miner is now talking about the coal industry in the past tense.

The little-noticed shift in rhetoric speaks volumes about how the United States' energy landscape has changed since Clinton last campaigned in 2008: oil and gas fracking have exploded and cheap natural gas has taken a huge bite out of coal.

In the intervening years the Obama administration has also proposed aggressive measures to tamp down greenhouse gas emissions from fossil fuels like coal, while once-powerful coal companies like Arch Coal, which declared bankruptcy last week, have lost their political clout.

The shift by Clinton is not without significant political risk. She will have to walk a fine line in trying to please the progressive activists she needs to win her party's nomination and working-class "swing" voters whose support will be crucial for the general election in November 2016. Ohio and Pennsylvania, in particular, have a lot of electoral votes, which are key to electing a new president.

Mindful of that, Clinton has been careful to pay tribute to the contribution coal miners have made to the American economy, but she has also made clear that they should be helped to find new jobs, and a new way of life.

Ed Rendell, former Democratic governor of Pennsylvania and Clinton ally, said an economic case for addressing climate change could resonate in his state, where the coal industry employs more than 36,000 directly and indirectly, according to the Pennsylvania Coal Alliance.

"Citizens, coal miners and executives are not dumb and they see the handwriting on the wall. Someone needs to tell them the truth and make it clear," he said in an interview.

Clinton’s campaign declined to comment on the shift in her coal message or how she plans to appease both environmentalists and coal workers.

"VOODOO ENVIRONMENT CONCERNS"

Democratic presidential candidate Hillary Clinton picks out fresh corn during a visit to Dimond Hill Farm in Hopkinton, New Hampshire July 28, 2015. REUTERS/Brian Snyder

Clinton was quick last week to praise President Obama's stricter rules on coal-fired power plants, vowing to both defend and build on them. Her stance won plaudits from environmentalists within her party, but unions, a key constituency, are concerned she has yet to say how tougher climate rules will affect coal industry jobs.

"We would like to see some more specifics regarding her energy policies," said Phil Smith, a spokesman for the United Mine Workers Association, which represents about 80,000 workers.

Roland "Butch" Taylor, a business manager at the Plumber & Pipefitters Local 396, a union in Boardman, Ohio, said he hopes Clinton does not cater solely to "voodoo environment concerns."

"A candidate should be pushing for clean coal technology until alternative energy is available," Taylor said.

In 2008, Clinton triumphed in the Democratic primaries in West Virginia, Kentucky, Ohio and Pennsylvania with a promise to make coal cleaner.

She told the environmental magazine Grist then: “You have got to admit that coal — of which we have a great and abundant supply in America — is not going away.”

She is no longer saying that but neither is she fully embracing the agenda of environmentalists in her party who want her to turn her back completely on fossil fuel industries.

Clinton was pressed at a town hall in Dover, New Hampshire, last month about why she had not promised to move more quickly to curb greenhouse gas emissions.

"I know what the right answer in terms of getting votes would've been," Clinton responded.

Holding up her hand to calm agitated activists, she added, "It's really easy to say 'yeah, let's ban all of these fossil fuel extractions’ and forget about all the people who are employed, who have jobs that rely on the energy."

But Clinton said that on climate, as on other issues, "I am going to tell you what I believe, and some people will like it, and some people may not like it."

The line drew applause that overtook chants from the dozen or so climate activists in the room.

Clinton's Republican opponents are almost certain to use her support of Obama's new measures to restrict greenhouse gas emissions from power plants to say she is part of what they call Obama's "war on coal."

CLINTON'S APPALACHIAN ROOTS

Democratic presidential candidate Hillary Clinton addresses supporters at a campaign kickoff event in Denver, Colorado August 4, 2015. REUTERS/Rick Wilking

Clinton has personal ties to the Appalachian region where the mining industry thrived for decades. She often talks about her grandfather's work in a lace mill in coal-dependent Scranton, Pennsylvania and her childhood summer vacations spent at a cottage in the area.

"We need to say to people in coal country: 'We are grateful for your service,'" Clinton said at a New Hampshire house party last month.

"They made it possible for this country, starting in the 19th century, to become an economic engine of prosperity," she said. "We've got to say 'what can we do to help you? How can we help you have a better future? What kind of investments can we help bring to coal country? How can we give you a stake in the future?"

Clinton has hinted that her climate plan - which she has yet to fully unveil - will be as much about focusing on boosting the middle class as it will be about the environment.

She plans in the coming months to release details of an initiative to protect the health care and pensions of coal workers.

She has also proposed eliminating capital gains taxes to encourage investment in hard-hit industrial states known as the Rust Belt, as well as expanding tax credits to prevent them from "spiraling downward after a major economic shift or plant closing."

Clinton met privately recently with a group of Capitol Hill Democrats and pitched them a rough outline of her climate plan.

U.S. senators Tim Kaine of Virginia and Joe Manchin of West Virginia both praised Clinton's recognition of coal's contribution to the U.S. economy but said any plan could not abandon the coal industry immediately, since it still provides one-third of the country's energy.

"I can't tell you how much I appreciated hearing a presidential candidate of her stature being able to recognize how we got to where we are today and how we move forward without leaving anybody behind," Manchin said.

(Reporting By Valerie Volcovici and Amanda Becker, editing by Caren Bohan and Ross Colvin)