The Post tells us about the exhaustive and exhausting efforts to get Trump to act like a responsible adult.

Silicon Valley titans, such as Apple chief executive Tim Cook and Tesla chief executive Elon Musk, contacted the White House directly, making clear just how seriously they viewed the issue of climate change — and how important it was to them that the president not withdraw from the international pact.

European leaders, including French President Emmanuel Macron and German Chancellor Angela Merkel, used a private summit of the Group of Seven world powers to repeatedly and urgently prod Trump to stay true to the climate deal.

But of course Trump is both stupid and conceited, so he never for a second thinks that these people are more intelligent and informed than he is and therefore he should pay attention to what they tell him. He just thinks they’re losers because, you know, not American, not tv personalities, not property tycoons. He’s way too stupid to understand how stupid he is.

Trump had never liked the Paris accord. He viewed it as a “bad deal” and during the campaign had promised his base he would “cancel” the climate pact that he believed was hurting American workers.

His final, deliberative verdict was the same as his initial, gut-level one, according to this account of Trump’s decision-making process, which is based on interviews Thursday with more than a dozen administration officials, Trump confidants, Republican operatives and European diplomats. Even so, the president listened and moderated months of often heated, and at times downright contentious, discussions among his own advisers, as well as scores of outsiders.

He likes that. It’s part of the game of playing president, and in the end he gets to do what he wants and laugh at all those people who tried so hard to make him think like a grownup.

“He’s stayed where he’s always been, and not for a lack of trying by those who have an opposite opinion,” said Kellyanne Conway, counselor to the president. “He started with a conclusion, and the evidence brought him to the same conclusion.”

A ringing testimonial to his obstinate stupidity and incompetence.

Ivanka Trump, meanwhile, helped lead the effort to stay in the deal. In meetings, she argued that withdrawing could hurt the United States’ global image and weaken its moral authority abroad. She and her allies pushed the case that the president would have more leverage if he remained part of the agreement and negotiated from within.

The opposing camp, however, dismissed the substance of her appeal, brushing off her concerns as a hand-wringing question: “What will the world think of us?”

Right, because that doesn’t matter at all and never has. We can get whatever we want just by demanding it and mentioning the nukes if anyone balks. It’s that simple and easy.

Some of the efforts to dissuade Trump from withdrawing actually had the reverse effect, further entrenching his original position. When Trump heard advocates arguing that the era of coal was coming to an end — something Cohn told reporters on last week’s foreign trip and also a frequent talking point by some cable news pundits — Trump only became more adamant that pulling out of the Paris pact could help rescue the U.S. coal industry, said a Republican operative in close contact with the White House.

Well there’s one thing you can say about coal. Ok it’s dirty, and it burns dirty, and it creates smog that corrodes people’s lungs and deposits layers of soot on everything, and it’s terrible for global warming, and it’s dangerous work, but – at least you can understand it. Lump of coal: fire: energy. It’s not all confusing and puzzling and invisible like nuclear energy or those weird solar panels. Energy should be simple and easy to understand at a glance. That’s a big plus for coal in our Donnie’s book.

Pressure from leaders abroad also backfired. One senior White House official characterized disappointing European allies as “a secondary benefit” of Trump’s decision to withdraw.

Naturally. They’re all smarter than he is, also politer. Naturally that makes Donnie from Queens angry. How dare any pesky European be smarter and more decent than Donnie the Boss?

When Trump touched down at a humid Sicilian air base last week, European leaders were already girding up for an argument at the G-7 summit. In Brussels, the president had just castigated NATO allies for their defense spending. But as leaders spoke during a closed-door NATO dinner, not one directly confronted him, seeking to save their political capital for a contentious discussion about climate change in Italy.

In the end, several officials said, the Group of Seven summit felt more like a Group of Six against One, at least on climate issues, as every other leader went around the table urging Trump to remain in the Paris accord.

“There is a situation where six — if you take the E.U., seven — stand against one,” Merkel said after the meeting.

Merkel, who might be the ­second-most powerful leader in the world after Trump, also pressed a moral-based argument, according to one official who was in the room. If the United States pulled out, what would be the message to countries in Africa that could suffer most from global warming and nations like Fiji that are drowning under rising sea levels?

The official added that another leader brought up political arguments: Does the United States want to preserve the U.S. lead on the topic or hand it off to China and India? And a third made an economic pitch: By encouraging renewable energy, you boost the economy, you boost innovation and you stay competitive.

But Trump seemed unmoved by any of the appeals, instead telling the group that this was what he had promised during his election campaign and that he was protecting his voters, according to the official.

On the plane back from Sicily, Merkel did little to hide her disappointment, according to someone who traveled with her. She raved about Macron and his “keen perception.” There was no such praise for Trump, of whom she could only say, “He listened for hours.”

Well obviously. She wasn’t going to be raving about Donnie’s keen perception, was she. The man is dumb as a stump.

People who made the mistake of deciding to work for Trump are also glum.

Among administration aides who wanted Trump to stay in the agreement, there was growing frustration, bordering on despondency, that they had been unsuccessful in their effort.

Many had given up high-paying jobs outside the administration, sacrificed their quality of life, and were facing daily leaks and palace intrigue stories — only to feel as if they had been unable to influence the president on an issue of top importance.

Silicon Valley executives and other CEOs were also upset. Lloyd Blankfein, the chief executive of Goldman Sachs, where he led the firm along with Cohn, took to Twitter for the first time ever Thursday to criticize the Paris withdrawal, writing, “Today’s decision is a setback for the environment and for the U.S.’s leadership position in the world.”

Musk, the CEO of Tesla, who had worked closely with Kushner on several of his key initiatives, also used Twitter to announce his departure from White House advisory panels: “Am departing presidential councils. Climate change is real. Leaving Paris is not good for America or the world.”

Donnie don’t care. Donnie got his revenge.