It's US First under Trump
Most of their protests -- by an array of anti-racist, anti-war, feminist, LGBT, and pro-immigration groups -- were peaceful, but sporadic violence marred the day.
Several hundred masked, black-clad protesters carrying anarchist flags smashed windows, lit fires and scuffled with riot police blocks from the parade held in Trump's honor, with at least 217 people arrested for vandalism.
Even the peaceful protesters were intent on spoiling Trump's party -- letting out a deafening roar as the presidential limousine rolled past.
“Not my president! Not my president!” they yelled, as the pro-Trump crowd in nearby bleachers chanted “USA! USA!”
'This carnage stops here'
For Trump's critics, there was disbelief that a man who 19 months ago hosted “The Apprentice” reality TV show is now leader of the free world -- sworn in with a 37 percent approval rating, the lowest on record, according to a CBS News poll.
Public interest lawyer Renee Steinhagen, 61, came from New York to join the protests.
“I'm doing this to express resistance to the change that await us,” she said. “This administration seems more extreme than any other. This is a simple act of resistance. It's better than staying at home.” Trump's inauguration caps the improbable rise of the Manhattan real estate magnate who has never before held elected office, or served in government or the military.
Rather than appealing to desire to bridge political divides and lift Americans' gaze to the horizon, his first address to the nation was deeply unorthodox.
Trump painted parts of America as a dystopian hell, with mothers trapped in poverty and “rusted-out factories scattered like tombstones across the landscape.” “This American carnage stops right here and stops right now,” he said.
It was a deliberate and striking contrast from the uplifting message of Obama, who was among the dignitaries in attendance.
Obama and his wife Michelle departed the Capitol by helicopter minutes after the swearing-in, turning a page on eight years of Democratic leadership in the White House.
Alliances
A first two Trump cabinet members were sworn in after being confirmed Friday by the US Senate. Both are retired generals: Secretary of Defense James Mattis, and Homeland Security Secretary John Kelly.
For the next few weeks the White House plans a series of daily executive orders to roll back Obama's agenda.
Trump has also vowed to re-examine long-running alliances with Europe and in Asia.
“We will reinforce old alliances and form new ones and unite the civilized world against radical Islamic terrorism, which we will eradicate completely from the face of the Earth.”