PAGE, Ariz. – For decades, waves of electricity poured from this behemoth of a power plant on the high desert plateau of the Navajo reservation in northern Arizona, lighting up hundreds of thousands of homes from Phoenix to Las Vegas as it burned 240 rail cars' worth of coal a day.

But as the day shift ended here at the Navajo Generating Station one evening early this year, all but a half-dozen spaces in the employee parking lot — a stretch of asphalt larger than a football field — were empty.

It was a similar scene at the nearby Kayenta coal mine, which fueled the plant. Dozens of the giant earth-moving machines that for decades ripped apart the hillside sat parked in long rows, motionless.

Saving these two complexes was at the heart of an intense three-year effort by the Trump administration to stabilize the coal industry and make good on President Donald Trump's 2016 campaign promise to end "the war on coal."

"We're going to put our miners back to work," Trump promised soon after taking office.

It didn't happen.

Despite Trump's stocking his administration with coal-industry executives and lobbyists, rolling back environmental regulations and intervening directly in cases such as the Arizona power plant and mine, coal's decline has only accelerated in recent years.

The failure to revitalize coal is now coming to play during his re-election campaign.

The story of the complex in Arizona demonstrates the lengths the administration went to in helping a favored industry, the limits of its ability to counter powerful economic forces pushing in the other direction and ultimately Trump's quiet retreat from his promises.

In the years after Trump's election, the federal government offered help valued at as much as $1 billion to keep this one power plant and coal mine up and running by embracing an industry plan to relax costly air-quality requirements.

A Republican lawmaker from Arizona sought to force one of the state's largest utilities to continue to buy power from the plant. Peabody, the world's largest coal company, offered to discount the price of the coal it was selling the power plant from the Kayenta mine.

None of it proved to be enough. By late last year, both the Kayenta mine and the Navajo Generating Station had gone offline, a high-profile example of the industry's broader collapse and the resulting economic and political aftershocks.

A similar story is playing out in North Dakota, where Great River Energy will shutter its big coal-fired power plant several years early, an extraordinary move that underscores the waning cost-competitiveness of coal in electricity production.

The Maple Grove-based company will close Coal Creek Station — one of the Upper Midwest's largest power plants — in the second half of 2022. It will be replaced to a great extent with new wind farms, including four in Minnesota.

The plant is adjacent to a coal mine, a big competitive edge. But due to dramatic changes in electricity markets in recent years, Coal Creek is losing money, and the coal operation is suffering as well.

Alvin Long, 61, who spent nearly three decades maintaining the earth-moving machines at the Kayenta mine in Arizona before it closed and remains unemployed, said the past several years have led him to reassess his political allegiance. After backing Republicans since the 1970s and voting for Trump in 2016, he said he was leaving the party.

"We really thought we had a chance to keep it going, when we voted for Trump," he said. "But I don't care to listen to him anymore. All of his promises went down the drain."

Market forces were working against Trump's efforts, primarily low natural gas prices that made coal a less attractive fuel for power plants and the increasing economic viability of renewable energy sources like solar and wind. The pandemic made matters worse, slowing coal sales as energy consumption in the United States dipped.

Far from bringing back jobs, the downturn has translated into 5,300 coal mining jobs, or nearly 10%, being eliminated since Trump took office.

At its peak in 1988, coal generated 57% of all of the electricity in the United States, while only 9% came from renewables, like solar, hydroelectric and wind.

But an examination of the administration's efforts to support coal in Arizona and elsewhere, including a review of thousands of pages of e-mails and other documents obtained under the Freedom of Information Act, also raises questions about whether the president had any realistic prospect of saving the industry or whether he mostly wanted to be seen as trying.

After all of the efforts the administration made in Trump's first three years in office, the White House has offered no big new plans this year to keep the industry afloat. The president rarely mentions it on the campaign trail.