It's "bad for business" remains one of President Trump's main reasons for opposing the Paris Climate Agreement and other policies to slow heat-trapping greenhouse gas emissions. But it's increasingly hard to square that dubious justification with the who's who of American business leadership lined up in strong support of staying in the pact.

So which CEOs did Trump heed as he weighed his decision, announced Thursday, that he's withdrawing from the historic 2015 agreement? It certainly wasn't David MacLennan, who heads Minnesota-based Cargill. Nor was it 3M's Inge Thulin, who, along with MacLennan and 28 other American chief executives, signed an open letter earlier this month urging the U.S. to remain in the Paris pact.

The missive, dated May 10, was published in the Wall Street Journal. Co-signers included the heads of General Electric, Cummins Inc., Coca-Cola Inc., and Proctor and Gamble Co. Also worth noting: Exxon Mobil Corp. supports staying in the accord, likely because the company sees an opportunity to make money from selling natural gas, a cleaner-­burning energy source found in abundance in the U.S.

Following through on the solid first step the Paris accord represents to safeguard the planet and future generations should have been more than enough reason to stay in. But in making his decision, Trump failed to see what even Exxon does: The switch to cleaner or renewable fuels is underway, and it represents a breathtaking economic opportunity.

Carelessly throwing away American leadership in the global agreement gives adversaries an opening they will seize. Countries leading on this will effectively corner research and development dollars. Innovation will happen beyond our borders. Instead of pioneering the technology that will power the future, Americans will buy it from German, Chinese or French corporations. How is that putting America first?

The pain about this in former South Carolina Republican congressman Bob Inglis' voice was obvious this week during an interview. Inglis now heads RepublicEn, a nonprofit group advocating free-market solutions to climate change. American firms, he said, are the best hope to rapidly develop clean energy technology. That's crucial because the window of time to prevent global temperatures from increasing to a harmful threshold is closing. The Paris agreement calls for holding global temperature increases to below 2 degrees Celsius this century.

"It's such an abdication of American leadership. It's where this populist nationalism is so wrong,'' Inglis said. "We aren't in the business of retreat. We engage."

The Paris pact has language that prevents an immediate exit for nations wishing to leave. Jumping through all the hoops won't be complete before the next presidential election.

Today's backward-looking presidential action should make future political candidates' climate policy stances front and center. Office seekers should not only embrace the Paris agreement, but move beyond that. In particular, it's time to get serious about Inglis' preferred solution — a revenue-neutral carbon tax that would give regulatory certainty to business and add considerable muscle to global climate action.

"One of the most striking things about climate change is the consensus among economists. … Economists tell us to add the hidden costs of burning fossil fuels into the price of those fuels. In a transparent, accountable marketplace, clean energy will win,'' Inglis said. "Fix the economics, fix the problem. It's really that simple.''

Voters in 2018 elections and beyond should also call out candidates who repeat the claim that climate-change action hinders the economy, as Trump did Thursday. Who, exactly, is saying that? American business leaders clearly are not.

Trump's decision is based on something other than science and expert advice. Voters in future U.S. elections shouldn't make the same mistake.