Donald Trump has been president for a month, and his supporters are already praising him for bringing back US coal mining jobs — even though he hasn’t, really. Here’s a sample quote from a Trump backer in Florida, via Jenna Johnson and David Weigel of the Washington Post:

“If he hadn’t gotten into office, 70,000 miners would have been put out of work” ... “I saw the ceremony where he signed that bill, giving them their jobs back, and he had miners with their hard hats and everything — you could see how happy they were.”

A few things to point out here:

The supporter is referring here to Trump’s repeal of the Obama administration’s “stream protection rule,” which would have placed new restrictions on coal companies dumping mining waste in streams. It’s true that coal companies hated this rule and claimed it would’ve killed thousands of jobs, but an outside analysis found that the job impacts would be minimal: repealing the rule will only boost annual mining employment by 124 jobs. Total.

To put this in perspective, the US coal industry has lost more than 30,000 mining jobs since 2009 — and is down to just 50,000 today. Repealing the stream rule isn’t going to come close to halting this decline:

The reasons for coal’s long-term job losses are complex, but analysts typically point to three big factors: 1) mining has become increasingly automated, meaning fewer jobs per ton of coal produced; 2) a glut of cheap natural gas from fracking has cut into coal’s market share, leading to a sharp drop in US coal production since 2008; 3) various Obama-era environmental rules have made it more costly to operate coal plants, which has pushed many utilities to switch to natural gas or renewables.

Trump has promised to attack No. 3 and repeal some Obama-era environmental rules. But he has nothing to say about Nos. 1 and 2. (On the contrary, he’s promised to expand US fracking, which would further hurt coal.) So anyone hoping Trump is “going to bring those miners back,” as he’s pledged, and restore the coal industry to its glory days is in for disappointment.

Here’s one way to see this. The Energy Information Administration recently looked at what would happen to US coal production if Trump repealed the Clean Power Plan, Obama’s big policy to cut CO2 emissions from power plants. The coal industry would be a bit better off, but it would still be facing serious long-term decline:

Without the Clean Power Plan, the EIA estimates that US coal production would rise to 2015 levels before sinking again. For context: In 2015, there were roughly 63,000 coal mining jobs — a little higher than today’s levels, but still lower than at any time since the 1980s.

And that’s a best-case scenario for miners. There’s reason to suspect the EIA might be overly optimistic about future coal production here. For one, the agency has long underrated wind and solar growth. Second, many states are mulling plans to close their coal plants and shift to cleaner sources even if the Clean Power Plan is killed — because they know that carbon cuts are inevitable. (See Emily Holden’s interview with utility regulators in Arkansas for a great example.) Third, automation is likely to expand, which means mining jobs wouldn’t necessarily return even if production rebounds.

So unless Trump plans to ban fracking or automation, about the most coal miners can hope for is either a modest increase in employment or a slower decline than would’ve otherwise been the case. Even some coal executives quietly admit this: “I don't think it will be a thriving industry ever again," mining CEO Robert Murray told SNL reporter Taylor Kuykendall before the election. At best, "it will be an extremely competitive industry and it will be half size. … The coal mines cannot come back to where they were or anywhere near it."

Whether that’s good enough for Trump’s supporters in coal country is something we’ll find out over the next few years. One possibility is that they’ll give him credit for helping the coal industry no matter what happens or what the numbers say — much like that Trump voter quoted above. After all, coal is declining more slowly than it would've under Hillary Clinton.

But another possibility is that they’ll feel angry and misled if jobs keep vanishing. Shortly after the election, NPR ran an interview with a miner in Wyoming who saw Trump as the industry’s last hope for reversing its long-term decline. “If he doesn't do what he says he's going to do,” the miner added, “you know, why are people going to vote for Republicans again?”

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