Former President Joseph R. Biden Jr. and former Vice President Kamala Harris listening to Mr. Trump’s inaugural address.

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If his first Inaugural Address was a relentlessly dark vision of “American carnage,” President Trump made his second one a paean to the power of one person’s ability to rescue a nation — specifically his.

The 47th president’s 29-minute address on Monday, just after noon, painted an even bleaker portrait of a country in disarray, one seized by “years of a radical and corrupt establishment,” with the pillars of society “broken and seemingly in complete disrepair.” America, he said, “cannot manage even a simple crisis at home, while at the same time stumbling into a continuing catalog of catastrophic events abroad.”

It was a misleading and incomplete assessment of a country that has a growing economy, with falling inflation, slowing illegal immigration, a record-breaking stock market, the lowest levels of violent crime in years and a military that has limited engagement in conflicts around the world.

In that way, it was a speech that went to the core of Mr. Trump’s political appeal: convincing his supporters that he — and he alone — can fix what ails (or does not ail) the country. And it represented a reprisal of how he framed his first presidency — as a constant fight against enemies, foreign and domestic.

Former President Joseph R. Biden Jr. and former Vice President Kamala Harris listening to Mr. Trump’s inaugural address.

“My recent election is a mandate to completely and totally reverse a horrible betrayal and all of these many betrayals that have taken place and to give the people back their faith, their wealth, their democracy and, indeed, their freedom from this,” Mr. Trump said on Monday, in the longest inaugural address in modern history.

“America’s decline is over,” he declared.

Mr. Trump pledged that the country was entering a “golden age,” as evidenced by his own fate — noting that he emerged victorious in the face of political opposition, legal wrangling and even two attempts on his life.

“I felt then, and believe even more so now, that my life was saved for a reason. I was saved by God to make America great again,” he said, adding later: “As you see today, here I am. The American people have spoken.”

Mr. Trump’s delivery of his speech was more restrained than the ones he gives at his boisterous rallies. Instead of looking out at a crowd of supporters spread across the Washington Mall, the new president — citing frigid weather — delivered his address to a relatively small group of dignitaries inside the crowded Capitol Rotunda, where the sound of his voice echoed off the marble floor.

He read the speech from a teleprompter, with apparently few of his trademark, off-the-cuff departures. It was more businesslike than some of his angry rants, and more dutiful than his first address, almost as if to say: “I’ve explained all of this to you before.”

But in terms of the substance of his agenda, he did not pull his punches.