For all of the shock and awe of President Trump’s first weeks back in office, much of it should come as little surprise. Many of his actions are extensions of his first-term agenda, when he pledged to crack down on immigration and bolster the country’s advantage in international trade.

But in a few important ways, Mr. Trump’s return to power has been signified by some profound ideological swings as he moves to remake Washington, America and the world. On both the domestic front and in foreign affairs, Mr. Trump has shifted to a different, even more aggressive approach toward the role of government and the posture of the United States on the global stage.

The 45th president was never much of a shrink-the-government conservative; in fact, he was as free spending as many Democrats and, thanks in large part to Covid-19 relief, left behind the largest peacetime government in history. But now the 47th president has unleashed Elon Musk to put the federal government through his “wood chipper,” as the billionaire put it, one agency after another. “BALANCED BUDGET!!!” Mr. Trump wrote on social media last week.