AFTER announcing on June 1st that America will abandon the Paris climate agreement, Donald Trump can at least claim to have honoured a campaign promise. Then again, as he also pledged to reinstate torture, eliminate the national debt in eight years and hail Iran’s supreme leader with “Hey baby!”, that isn’t saying much. And the president’s decision to withdraw from the accord is similarly unconscionable and fatuous. A repudiation of his predecessor’s main climate policy, it was opposed by most of Mr Trump’s advisers, most large American firms and two-thirds of Americans. Mr Trump has dealt a severe blow to America’s interests and standing.

More hot air than a flue-gas stack

The Republicans who had been arguing to leave Paris, including Scott Pruitt, who disputes that people cause climate change and heads Mr Trump’s Environmental Protection Agency, consider this as merely consistent with George W. Bush’s decision to exit the Kyoto protocol in 2001. Yet Mr Bush, though misguided, at least had an economic argument. Kyoto imposed binding greenhouse-gas emissions cuts on rich countries but not on fast-growing developing ones, such as China, which overtook America to become the world’s biggest polluter only six years later.

The Paris accord is different. All its signatories—which is to say, every country except Syria, Nicaragua and now America—have undertaken to reduce emissions against business-as-usual targets. By withdrawing, Mr Trump has signalled that America will neither honour its agreements nor moderate its pollution, even as governments take measures to do so in much poorer countries, such as India, whose emissions per head are a tenth the size of America’s. That is unconscionable.

The fatuous part is for Mr Trump to claim that his decision is designed to invigorate American coal mining. There is no reason to expect that it will. Miners are struggling mainly because cheap and plentiful natural gas is taking coal’s markets. Even if Mr Trump truly believes that climate-change policy is to blame, he had no need to withdraw from Paris, because America’s commitment—a 26-28% cut in its 2005 level of emissions by 2025—was so modest. America is almost halfway to meeting that target even before adopting many of the environmental strictures Barack Obama had envisaged. Had Mr Trump elected to stay in Paris, but still dismantled those putative curbs on burning coal, America might have met its target anyway. And even if it had not, it would have lost nothing but face—which is why Rex Tillerson, who was the boss of Exxon, an oil giant, before he became secretary of state, argued for staying in.

Why did Mr Trump ignore him? Perhaps because, at the G7 meeting in Sicily last month, he sensed his fellow leaders disliked him, even as they urged him not to withdraw. Or maybe because he wanted to divert attention from the scandals plaguing his White House. Those are just guesses. Yet Mr Trump has made such a mockery of diplomacy and policymaking that the world is readier to believe them than his ostensible reason for withdrawing from one of the most successful international accords of recent years.

The tragedy, as so often with Mr Trump, is that if he were only more like the pragmatic problem-solver he claims to be, he could have done some real good. Climate policy, a jerry-rigged system of subsidies and compromises, in America and everywhere, needs an overhaul. A growing number of Republicans want a revenue-neutral carbon tax. As this newspaper has long argued, that would not only be a better way of curbing pollution but also boost growth. A truly businesslike president would have explored such solutions. Mr Trump has instead chosen to abuse the health of the planet, the patience of America’s allies and the intelligence of his supporters.