Donald Trump won the Republican nomination for president because — stop laughing — he crafted a brand as the Man Who Speaks Truth to Power.

But that evaporated with Trump’s much-trumpeted speech on energy policy — when He Who Can’t Be Bought showed he has given K Street’s fossil-fuel crowd a steep discount. In a speech that could have been written by lobbyists for oil and coal, Trump came out for the future — coal instead of cheaper, cleaner wind power, offshore drilling with light regulation and the Keystone XL pipeline. With his usual nonsensical patter of insults sprinkled like salt on a rancid meal.

And in so doing, he lit up his campaign’s only real rationale like a Memorial Day barbecue.

“ Donald Trump is not a conventional capitalist, so why would he grasp that what happened to coal and oil has been Capitalism 101? ”

The oil-and-natural-gas industry “supports 10 million high-paying Americans jobs and can create another 400,000 new jobs per year,” Trump said. “Compare this future to Hillary Clinton’s Venezuela-style politics of poverty.”

Feel like you’ve heard this before? You have.

“The oil-and-natural-gas industry’s total employment impact on the national economy amounted to 9.8 million full-time and part-time jobs in 2011,” a 2013 report from the American Petroleum Institute said.

The speech was dumb on 100 levels, but its real damage to Trump’s campaign comes from noticing that Trump hopped into the sack with an industry that gave $80 million in 2012, overwhelmingly to Republicans, but has ignored Trump while giving $56 million so far this election cycle. Mirabile dictu — this happened weeks after concluding he couldn’t self-finance a general-election bid.

It could hardly have been less subtle: Trump even cited the Institute for Energy Research, a “think tank” founded by a lobbyist for Koch Industries.

Trump’s not a conventional capitalist, so why would he grasp that what happened to coal and oil has been Capitalism 101? Certainly as a Washington Outsider, he can’t be expected to know Obama’s Clean Power Plan, which he says is killing the coal industry by making utilities drop coal, hasn’t been implemented yet.

He’s only running for president.

Coal companies are collapsing because cheap natural gas made their product too expensive, period. Coal gets competitive for electricity when natural gas costs $6 per million British thermal units of heat generated, and gas peaked near $13 in 2008. Today, gas futures cost $2.16 per mmBtu. Oil is broadly the same story. Gas will still be cheap if the Clean Power Plan goes away.

Donald Trump rewrites the rules on media coverage

Prices collapsed because of fracking, which flooded markets after 2008. Because coal has lost a third of its market share in U.S. electricity, mostly to natural gas, U.S. carbon emissions from power generation are down 21% since 2005.

That’s a good thing achieved at essentially no cost to consumers, thanks to regulatory forbearance (Obama could’ve banned or limited fracking) and capitalist ingenuity. For all Marco Rubio’s warnings of doom if coal is phased out, annual electricity inflation is 1.4% since 2009’s end, versus 7% in George W. Bush’s second term. Tax credits that have tripled renewables usage at the same time cost peanuts.

Why would Trump take such foolish stances, with analyses that high school kids can see through?

There’s always “he hates political correctness” — he says dumb things to exasperate liberals. That’s mature. It’s certainly not jobs; wind energy provides more jobs than coal mining. The U.S. economy replaces the equivalent of every coal-mining job in America in a good week, without flooding Miami.

Or did The Donald learn a general-election campaign will cost up to $1.5 billion he doesn’t have? He began the race with less than $300 million in personal cash, then lent his campaign most of the $55 million it spent through April, the Center for Responsive Politics says. Campaigns usually repay such loans from donations. But Trump’s campaign had only $2.4 million on hand as of April 30.

Presto! A man with nary a previous thought on energy policy becomes a staunch ally of coal, which gives 96% of its donations to Republicans, and oil and gas, which directs two-thirds of its largesse — $80 million in 2012 — to the GOP. And the Henry Higgins role in his transformation to energy savant is played by a Koch brothers adviser.

Ross Perot had a phrase for this: Don’t you find that fascinatin’?

There’s another explanation, hardly more flattering: Lobbyists capture politicians with selective knowledge as often as money. If a pol doesn’t know much, he’s owned by whoever feeds him arguments. As Trump bones up on energy, he’s spouting lobbyists’ lines, undigested, because he’s cramming. Which means he’s getting played.

If you need a guide to Washington, Mr. Trump, Sen. Elizabeth Warren is free.

It’s hard to play Man Speaking Truth when you don’t know what the truth is. Harder still when you need myth-sellers’ money. Hardest is to run as He Who Can’t Be Bought when you’ve given it up as easily as Trump has, before donations even flow. His whole campaign is a brand, which he lit up in high-carbon flames. Himself.

Tim Mullaney covers economics and politics for MarketWatch.