WASHINGTON, D.C. — In his first, fiery words as the nation’s 45th president, Donald John Trump presented a nationalist vision of America, breaking with tradition to invoke his unapologetically raw campaign, rebuke the country’s principal political parties and offer a populist ode to the “forgotten” people who, against all odds, elected him.

“Today, we’re not transferring power from one administration to another, or from one party to another, but we’re transferring power from Washington, D.C., and giving it back to you, the people. For too long, a small group in our nation’s capital has reaped the rewards of government while the people have borne the cost,” Trump told energized supporters gathered under damp skies along the National Mall.

“That all changes starting right here and right now, because this moment is your moment. It belongs to you.”

Deploying unusually gritty rhetoric for an inaugural address, Trump, 70, portrayed a bleak nation in need of saving — and cast himself as the savior, much as he did last July when he accepted the nomination at the Republican National Convention. He described “mothers and children trapped in poverty in our inner cities, rusted-out factories scattered like tombstones across the landscape of our nation; an education system flush with cash but which leaves our young and beautiful students deprived of all knowledge; and the crime and the gangs and the drugs that have stolen too many lives and robbed our country of so much unrealized potential.”

“This American carnage stops right here and right now,” Trump declared.

The only president never to have previously held public or military office, Trump promised to snuff out “radical Islamic terrorism” and protect Americans, whom he called “God’s people.” He vowed to end the slide of a nation he characterized as too deferential to other countries. He pledged to restore factory jobs, secure the nation’s borders, expand airports and railways and focus inward on America’s needs.

“From this day forward, it’s going to be only America first,” he said. “America first.”

Trump’s speech, which lasted just under 17 minutes as violent protests flared across D.C., began at exactly noon Friday, the day set in the Constitution for presidents to take the oath. He placed his left hand on two Bibles — one used by Abraham Lincoln when he became president in 1861 and the other given to Trump by his mother in 1955 — raised his right hand and, repeating after Chief Justice John Roberts, swore the most solemn words in American democracy’s vaunted peaceful transfer of power: to “preserve, protect and defend the Constitution of the United States.”

From artillery on the West Front of the U.S. Capitol reverberated a 21-gun salute. From hundreds of thousands of people huddled as far as the eye could see under damp gray skies along the National Mall came a roar of unfiltered joy. They had witnessed the inauguration of an unprecedented president, a brash New York celebrity developer who channeled deeply felt dissatisfaction with a rapidly changing global order into an astonishingly successful, unorthodox campaign buoyed by defectors of the political left and right.

“What truly matters is not which party controls our government, but whether our government is controlled by the people. January 20, 2017, will be remembered as the day the people became the rulers of this nation again,” Trump said. “The forgotten men and women of our country will be forgotten no longer. Everyone is listening to you now.”

Toward the end of his well-polished speech, which despite its overtly political tone was more embellished than his usual remarks, Trump turned more conciliatory, envisioning the unification of a divided country through patriotism.

“A new national pride will stir ourselves, lift our sights and heal our divisions,” he said.

But the bulk of Trump’s address, drafted in part at his Palm Beach estate of Mar-a-Lago, was defiant and reminiscent of his polarizing campaign — and the crowd loved it. In unison, it chanted with the president as he built to his trademark: “Make America Great Again.”

As Trump walked away from the rostrum and shook Barack Obama’s hand, the now-former president mouthed the words, “Good job.”

Befitting a nation deeply riven by politics, the pageantry inside the security perimeter contrasted with the tumult outside it, as protests raged across Washington, prompting police barricades, tear gas and flash bangs just blocks from the inaugural parade. Nearly 100 people were arrested. In the morning, protesters tried to block attendees from entering the Mall at several locations. They clashed with police after smashing ATMs and storefront windows.

John and Heather Paulson, a Jacksonville, Fla., couple that two years ago moved to Virginia, had trouble finding entry onto the lawn due to Black Lives Matter protesters blocking their way near Judicial Square.

“We didn’t really want to get in the middle of all that,” Heather, 35, said, gesturing toward the chanting protesters who had linked arms to block the way.

Discord between the inauguration and intensely blue Washington was palpable in the day leading up to the ceremony. Neighborhoods away from the Capitol, Mall and White House seemed almost deserted before the swearing-in, with glum residents reluctant to bid farewell to the Obamas and welcome the Trumps. In addition to hawking Trump gear, some peddlers offered “Goodbye, Obama” memorabilia.

After Trump took the oath, the streets simmered with tension from scattered demonstrations in opposition to the new president. Helicopters circled overhead as the sound of sirens filled the streets.

Trump enters office with the lowest incoming-president approval in modern times, following a bitterly divisive election in which he lost the popular vote and a 72-day transition in which he made few overt attempts at conciliation. Trump appointed no Hispanics — and no Democrats, as is tradition — to his Cabinet. Six days before his swearing-in, he was feuding with a civil-rights icon and congressman on Twitter, prompting at least 67 Democratic lawmakers to skip the inauguration.

But the political math favors Trump: Republicans control both chambers of Congress (and a majority of governorships and state legislatures) and could empower the new president to enact a sweeping agenda — assuming conservative lawmakers find agreement with a president of unfixed ideology sometimes at odds with their own.

“He’s been underestimated often but he’s never let it stop him from succeeding,” Senate Majority Leader Mitch McConnell of Kentucky said while toasting Trump during the day’s congressional luncheon. “May you unite our country behind a common vision.”

The nation’s 58th inauguration comprised three days of revelry in Washington, which bustled — at least in the areas around the celebration — with Trump supporters who had traveled in from across the country. Official crowd estimates for the swearing-in were not immediately available, but overhead camera shots showed the number was undeniably smaller than the 2 million who turned out to the 2009 inaugural of the first black president. Onlookers along parts of the parade route were sparse.

As Trump took the 35-word presidential oath, his wife, Melania, and their 10-year-old son, Barron, looked on beside him. A few steps away were Trump’s four adult children — Donald Jr., Ivanka, Eric and Tiffany. Also on hand: Obama, who along with his wife, Michelle, jetted off one last time Friday on the executive 747 airplane — no longer designated Air Force One for an ex-president — to Palm Springs, Calif., for a desert vacation.

An ailing former President George H.W. Bush was absent (“My doctor says if I sit outside in January, it will likely put me six feet under,” he wrote Trump, excusing himself), but all other living ex-presidents — Jimmy Carter, Bill Clinton and George W. Bush — were present. So was Trump’s rival, Hillary Clinton, who on occasion even smiled as she endured the experience of watching someone else assume the presidency she probably thought was hers. She and Trump shook hands later, and the newly minted president said he was honored by her presence at a congressional luncheon, where she received a round of applause.

Minutes before Trump took his oath, Vice President Mike Pence was sworn in by Associate Justice Clarence Thomas.

An anxious, excited crowd broke into chants of “USA!” and “Trump!” that built from the back of the National Mall to the Capitol as they waited for the president-elect to shed the hyphen.

Though he firmly departed from inaugural tradition in his address, Trump engaged in other familiar pomp. After the swearing-in, he had lunch at Statuary Hall in the Capitol with members of Congress. He attended the parade up Pennsylvania Avenue, getting out of his limo in front of his Trump International Hotel to walk and wave. He was expected to speak — and dance — in the evening at three inaugural balls.

The Trumps and Pences began their day with a religious service at St. John’s Episcopal Church, also in keeping with past inaugural protocol. Trump and his wife then shared a morning tea and coffee breakfast with the Obamas at the White House — one final, private meeting before one administration ended, and another began.