President Trump digs coal, if the ubiquitous rally signs from his 2016 campaign are to be believed. It’s a clearly accurate statement when considering the colloquial/Fonzie use of “dig” and a clearly inaccurate one when considered literally. The message Trump sought to send during that election was somewhere in the middle: He would prioritize coal mining as both a refutation of the environmental policies of President Barack Obama and as an exemplar of Real American Jobs.

As president, Trump has on occasion tried to wrap coal mining jobs into one of the “promises kept” that his current rally signs tout. He did so in a tweet on Friday, lifting up a point made by Senate Majority Leader Mitch McConnell (R-Ky.).

Coal mining jobs are not coming back fast. When Trump took office, about 50,900 people worked in coal mining, according to the Bureau of Labor Statistics. In January, about 51,300 did. A subtle shift, one-fifth of the change from July 2016 to January 2017 under Obama.

What’s more, those numbers are national. In Kentucky specifically, the number of coal miners has dropped during Trump’s presidency.

Granted, those numbers are still better than what the industry saw in either of Obama’s terms. In the last four years of Obama’s presidency, coal mining employment fell by nearly 26,000. Employment in Kentucky fell by 6,300, compared to a drop of about 2,000 so far in Trump’s term in office.

But it is not really the case that the drop under Obama was primarily a function of his policies. It was much more a function of the improvement of hydraulic fracturing techniques in the United States, a change that led to a boom in natural gas extraction and, subsequently, a drop in natural gas prices.

During President George W. Bush’s second term, a thousand cubic feet of natural gas used for generating electricity cost an average of $8.02. During Obama’s first term, it averaged $4.69. In his second term, $4.06.

There wasn’t an immediate relationship between those price drops and the decline in coal employment, which didn’t start to fall rapidly until 2012.

That drop in price was coupled with a 14 percent increase in the price of coal from 2008 to 2011.

“The decline in coal use and coal emissions is linked to the decline in the price of natural gas relative to the price of coal, not to the number of coal plants that are replaced with natural gas plants,” a recent report said. “Natural-gas-driven changes in electricity prices have caused coal plants to close, and the retired generation capacity has been replaced with a mix of natural gas plants and renewable sources.”

That report came from the White House Council of Economic Advisers. It was released Thursday.

That excerpt focuses on electricity generation, one of the main drivers of demand for coal in the United States. Under Obama, there was a rapid shift from generating electricity by burning coal to burning natural gas, a shift that stemmed “from lower natural gas prices reducing reliance on electricity generated from coal,” according to the Council of Economic Advisers report. Late in Obama’s second term, more electricity was generated from natural-gas-burning plants than coal plants.

The economics of fracking ended up pushing electricity suppliers to cleaner-burning fuels, reducing greenhouse gas emissions from electricity generation. But that shift also meant less demand for coal and, therefore, for coal mining.

Trump wanted voters in 2016 to think he’d resuscitate the coal industry. He wants voters in 2020 to think he has. Unfortunately for his political rhetoric, the economy — at least on this point — is working against him.