Washington (AFP) - Donald Trump vowed a new “golden age” as he took the oath for a historic second US presidential term Monday, painting a picture of an America in decline that only his hardline policies can restore to glory.

In an often divisive address in the US Capitol, the 47th president promised a blitz of orders including the declaration of a national emergency on the Mexican border and a policy of only recognizing two genders.

Trump also struck a nationalistic tone as he capped the most extraordinary comeback in US political history, pledging to impose trade tariffs, rename the Gulf of Mexico the Gulf of America, and take “back” the Panama Canal, which has been controled by the Central American country since 1999.

“The golden age of America begins right now. From this day forward our country will flourish and be respected again all over the world,” Trump said in the Capitol, where the inauguration was held indoors for the first time in decades, due to freezing weather.

The Republican even appeared to suggest he was on a divine mission, saying “I was saved by God to make America great again” after escaping an assassin’s bullet at an election rally in July.

While promising renewal, Trump harshly denounced what he said had been a “betrayal” of Americans by a “radical and corrupt establishment” under outgoing President Joe Biden.

“America’s decline is over,” said Trump, who at 78 is now the oldest president ever to take office.

Biden, 82 – who had earlier hosted Trump and his wife Melania at the White House for tea – watched stony-faced as his political nemesis read the last rites over his single term in office.

- ‘National emergency’ -

Trump was surrounded by America’s wealthy and powerful for the inauguration, in the same building that his supporters attacked in January 2021 as they tried to overturn certification of his election loss to Biden.

Elon Musk, the world’s richest man, plus Meta boss Mark Zuckerberg, Amazon chief Jeff Bezos and Google CEO Sundar Pichai all had prime seats in the Capitol alongside Trump’s family and cabinet members.

Tesla and Space CEO Musk – who will lead a cost-cutting drive in the new administration – later told a rally that Trump’s victory was a “fork in the road of human civilization.”

Former presidents Barack Obama, George W. Bush and Bill Clinton all attended the ceremony with their spouses – except for ex-first lady Michelle Obama who pointedly stayed away.

Trump will now kickstart his new term with a host of executive orders.

“I will declare a national emergency at our southern border” with Mexico and move troops to the border, Trump said to loud cheers inside the ornate Rotunda hall, while vowing to deport “millions and millions” of illegal immigrants.

Trump said his government would recognize “only two genders, male and female,” ending the current practice of providing a third gender option in some settings, and scrap government diversity programs.

He will also pull Washington out of the Paris climate accord aimed at halting global warming, expand oil production and “drill, baby, drill”, and scrap rules aimed at persuading motorists to buy electric vehicles.

Finally he vowed to “plant the Stars and Stripes” on the planet Mars.

“I feel on cloud 10,” Gregg Donovan, a 65-year-old from Hollywood wearing a top hat with a photo of Trump tucked into the brim, said outside the Capitol after Trump was sworn in.

- Biden pardons -

After delivering his focused half-hour inaugural address Trump soon returned to form – riffing on subjects ranging from immigration to his wife’s hat and shoes in a rambling speech to supporters at the Capitol.

He also repeated his lie that he had won the 2020 election – a lingering and unprecedented effort to cast doubt on US democracy.

In a split-screen moment as Trump spoke, an emotional Biden told staff that “we’re leaving the office but we’re not leaving the fight.”

He then boarded a final flight to California.

Biden’s extraordinary last acts in office showed his own disdain for Trump, whom he faced in the 2024 election before concerns about his age forced him to drop out.

He preemptively pardoned former officials and his own siblings to shield them from “baseless and politically motivated investigations” under Trump.

Yet Biden also tried to restore a sense of tradition to the inauguration after Trump skipped his in 2021, inviting Trump and Melania to the White House for tea.

Trump is just the second president in US history to return to power after being voted out, after Grover Cleveland in 1893.

He is also the first convicted felon to be president, related to paying a porn star hush money during his first presidential run.

Russian President Vladimir Putin congratulated Trump and said Monday he was open to talks on the Ukraine conflict.

Israeli Prime Minister Benjamin Netanyahu also congratulated Trump – whose team helped broker a Gaza ceasefire deal.