Milei, 53, a former television pundit who shot to fame with expletive-ridden tirades against rivals, China, and the pope, took the presidential sash from outgoing Peronist Alberto Fernandez in a packed Congress with crowds gathered outside.

The wild-haired outsider marks a major gamble for Argentina; his shock therapy economic plan of sharp spending cuts has gone down well with investors and could stabilise the embattled economy, but it risks pushing more people into hardship with over two-fifths already in poverty.

However, voters – who drove Milei to victory in a November run-off against a ruling Peronist coalition candidate – said they were willing to roll the dice on his sometimes radical ideas that include shutting the central bank and dollarising.

“He is the last hope we have left,” said 72-year-old doctor Marcelo Altamira, who slammed “useless and inept” governments for years of boom-bust economic crises. The outgoing Peronist government, he said, “had destroyed the country”.

The challenges are huge. Argentina’s net foreign currency reserves are estimated at US$10 billion in the red, annual inflation is 143% and rising, a recession is around the corner, and capital controls skew the exchange rate.

Argentina has gone through boom-bust cycles for decades with money printing to fund regular deficits stoking inflation and weakening the peso. That has worsened in recent years as reserves have dwindled with a major drought earlier this year hitting main cash crops soy and corn.

The major grains exporter needs to revamp a creaking US$44 billion loan programme with the International Monetary Fund (IMF), while Milei needs to navigate ties with important trade partners China and Brazil, whom he criticised during the campaign.

Milei will take over from unpopular outgoing centre-left President Fernandez, but will need to negotiate with rivals as his libertarian coalition only has a small bloc in Congress. He has allied with the main conservative grouping.

That has already had an impact. He has moderated his tone in the last few weeks, packed his first Cabinet with mainstream conservatives rather than ideological libertarian allies, and put more radical ideas like dollarisation onto the back burner.

That has helped to buoy the markets and reassure voters.

“I think he will do well. For legal and Congressional reasons he’ll end up having to focus on more coherent things,” said Laura Soto, 35, a restaurant employee in Buenos Aires.

She said some more radical social ideas he had talked about during the campaign were also unlikely to happen, including easing regulation on guns and reopening the debate on abortion, which was legalised in Argentina three years ago.

‘Change was necessary’

To fix the economic mess, Milei has chosen mainstream conservative Luis Caputo to helm the economy ministry, with a close Caputo ally Santiago Bausili as the central bank chief.

Milei is expected to lay out his vision in a speech today, with a more detailed economic plan likely on Tuesday or Wednesday, sources from his team told Reuters.

The ceremony’s guests included Ukraine’s president Volodymyr Zelensky, Hungary’s prime minister Viktor Orban, and a US delegation.

Right-wing former Brazilian leader Jair Bolsonaro also attended, as well as Uruguay’s conservative leader Luis Lacalle Pou. Chile’s leftist President Gabriel Boric was also present but leftists Luiz Inacio Lula da Silva of Brazil and Mexican Andres Manuel López Obrador will be some of the major absences.

Attentive to the popular support that’s driven his rise, Milei is expected to speak to his supporters outside Congress, instead of doing so to lawmakers inside as is customary.

“He gives us something, the people, not the politicians,” said retiree Vilma Bonino, 73. “Now we need to see what happens.”

In a sign of challenges ahead, state energy firm YPF hiked petrol pump prices this week by an average of 25%, with analysts and markets anticipating a sharp devaluation of the over-valued peso currency shortly after Milei takes office.

“Things aren’t in good shape currently and it seems to me that a change was necessary,” said 22-year-old student Delfina Ortiz as she took a photo in front of Congress.

“Obviously, like all change, there is a lot of hope and expectation for what is to come. Hopefully it will be good.”