The Divider: Trump in the White House, 2017-2021 by Peter Baker and Susan Glasser:
Back in Washington, the president was taking an increasingly expansive view of his own powers. That July, he told a conference of pro-Trump teenagers that Article II of the Constitution gave him “the right to do whatever I want as president,” which was both flagrantly incorrect and also consistent with Trump’s oft-stated view that he had the “absolute right” to do whatever he wanted at whatever moment he wanted to do it—a list that had grown by that point to include everything from pardoning himself and declaring a national emergency to build a border wall to revealing classified information. He not only admired autocrats like Putin and Xi, he appeared determined to sound like one. And the presidential ego, never slight, seemed ever more boundless by the middle of 2019 as he often referred to himself as a “genius” and one of “the smartest people anywhere in the world.”
His estimation of his abilities was both vast and highly specific. The list of things Trump publicly claimed to “know more about than anybody” had grown to include borders, campaign finance, courts, construction, drones, debts, Democrats, the economy, infrastructure, the Islamic State, lawsuits, money, nuclear weapons, politicians, polls, renewable energy, social media, steelworkers, taxes, technology, “things” generally, trade, the United States government, and the visa system. He even said he knew more about New Jersey Democratics senator Cory Booker than Booker knew about himself. The president often explained publicly that windmills caused cancer, climate change was a hoax, and American toilets did not work properly anymore because of federal regulations.