(Daron Taylor/The Washington Post)

President Trump’s decision to withdraw the United States from the Paris climate agreement represents the clearest statement yet of convictions and principles that make up his worldview. “America First” is more than a mere slogan to this president. It is the sum of long-standing beliefs — and grievances — about the way things are and ought to be.

The decision on the Paris agreement was obviously going to be controversial, with potentially major consequences for America’s role in the world and its future ability to lead on environmental and other issues, as this country has done during and since World War II. But as controversial as it is, and as significant a turning point as it appears to represent, the decision was anything but shocking.

Trump’s presidency and his campaign are the embodiment of a set of views shaped long before he became a politician. The Paris decision was cast in the context of repairing the economic disadvantages of a generation of global agreements that he has railed against for decades.

White House chief strategist Stephen K. Bannon walks out after President Trump speaks on the Paris climate change accord in the Rose Garden at the White House, on Thursday. (Jabin Botsford/The Washington Post)

Trump oversees a White House that many times lacks focus, discipline and harmony. Often that seems to sum up the president himself. That shouldn’t negate the reality of what drives the president, which is a belief that others have taken advantage of the United States and that he alone will stop it. His announcement on Thursday was biting in his sense of resentment that the Paris pact was a collective effort by the rest of the world to punish this country.

Many issues are new to the president, and on these he has few fixed views. Nowhere has that been more evident than in the debate over health care. It’s easy to mock Trump for saying earlier this year, “Nobody knew health care could be so complicated.” For him it was a discovery, and he has yet to master the details or seemingly care much about them. His statements about health care have been varied and often contradictory. If he gets a bill on his desk, he will sign it. Health care is about posting a victory.

On core issues, however, Trump’s views are consistent and long-standing. Those views are viscerally expressed, not intellectually argued, but it has always seemed clear that they are deeply and genuinely felt. Perhaps that is an act. He is a great showman above all. But on matters of trade and jobs, the president has rarely wavered or been given to changing his positions. Added to that, during the campaign, were hardened views about illegal immigration, and he has acted on them as president.

He was lobbied heavily on what to do about the Paris accords. The power centers of his White House and administration set themselves against one another, as my colleagues Ashley Parker, Philip Rucker and Michael Birnbaum explained in a well-reported piece about the decision-making.

Trump heard from many people over time: those in his inner circle; chief executives of major companies; world leaders when he was in Europe. In the end, he wasn’t swayed by those who urged him not to take the drastic step of pulling out. His view that the climate agreement penalized the United States economically prevailed.

Some people have explained the decision as Trump’s keeping a campaign promise, or staying true to his base at a time when his presidency is being buffeted by controversy over Russia and other matters. All true, but to see the decision as merely that may miss an essential ingredient about the Trump presidency. He might not be quite as malleable as some suggest.

White House Chief of Staff Reince Priebus, Environmental Protection Agency Administrator Scott Pruitt, and Vice President Pence clap as President Trump speaks about the Paris climate change accord in the Rose Garden at the White House, on Thursday. (Jabin Botsford/The Washington Post)

The decision also could help to provide context to the ongoing conversation about who holds power in Trump’s White House. Almost since Inauguration Day, fueled by leaks from one faction or another, the media have charted the apparent ups and downs of key advisers, a real-life “Game of Thrones.”

In the early days of the administration, chief strategist Stephen K. Bannon was the presidential Svengali, the architect of the Trumpian view of the world and the shaper of a dark, dystopian vision that the president was embracing.

Later came the rise of the “moderates” and corporate types from New York: his daughter Ivanka Trump; her husband, Jared Kushner; chief economic adviser Gary Cohn; and deputy national security adviser Dina Powell. They were in league trying to steer the president toward a more moderate course. In that narrative, Bannon was diminished and in retreat.

Now with the climate decision, Trump appears to have embraced Bannon’s view that global agreements are inherently harmful to the United States while rejecting the views of his daughter, Cohn, Secretary of State Rex Tillerson and others, who warned against an abrupt break from Paris because of the damage it could do to the country’s — and the president’s — reputation around the world.

But in siding with Bannon, the president also embraced the views of many conservative Republicans, including Scott Pruitt, the administrator of the Environmental Protection Agency, who oppose most of the environmental policies of former president Barack Obama’s administration. Amid criticisms from Democrats, some corporate chiefs and America’s European allies on Thursday, there was a sizable chorus of cheers coming from many GOP elected officials and other conservatives who don’t necessarily embrace Bannon’s views about globalism. Their views are best represented inside the White House by Vice President Pence.

In the end, all the intrigue about staff infighting, though certainly real and sometimes debilitating for the smooth running of an administration, overlooks the central figure of the president. He remains the captain, and on a few core issues, his will wins out.

The Paris decision represented a Trumpian view of the world, and America’s place in it, that was articulated by Cohn and national security adviser H.R. McMaster, in a recent Wall Street Journal op-ed. They rejected the notion of a “global community” of nations in favor of a more ruthless arena for competition among nations fueled by self-interest. America, they said, was well positioned to prevail in that competition.

Cohn and McMaster argued that “America First” does not mean “America alone.” But Trump’s approach seems to embrace the idea that the United States will gain competitive advantage economically operating alone and with its own interests in mind, a highly transactional approach that the president underscored when he said he could try to make a better deal on climate than the Paris agreement, though there is no current forum in which to do so.

Implicit in his statement about the Paris agreement was the assertion that his approach will produce more jobs, more economic wealth and a better life for the working men and women who have been harmed by past global agreements, whether on trade or the environment, and who were his core supporters in November. Or at least his decision to withdraw will prevent the further loss of jobs for those forgotten Americans, as he has described them.

Early in his administration, Trump said he had been elected president of the United States, not president of the world. On Thursday, he returned to that theme, saying he was elected “to represent the citizens of Pittsburgh, not Paris.” (The mayor of Pittsburgh quickly said he opposed Trump’s decision on the climate agreement.) That kind of language alarms many internationalists, here and abroad. But it remains at the core of the president’s thinking, and he will continue to act on it.