Brazil is anticipating a knock-on effect to its foreign policy, trade, policing and even how political campaigns are fought.
Brazil's Latin American neighbours are bracing for a regional "Bolsonaro effect" after the far-right leader's crushing victory in presidential elections.
The knock-on effect will be felt across the region in foreign policy, trade, policing and even in how political campaigns are waged, analysts said.
Bolsonaro's win perpetuates electoral routs for right-wing presidents against leftist governments hostile to the United States, said Argentine commentator Pablo Seman - citing recent victories for Mauricio Macri in Argentina, Sebastian Pinera in Chile and Mario Abdo Benitez in Paraguay.
"The US is taking possession of what has been lost in Latin America, in a context of global struggle with China for natural resources, markets, political support. There is no place in Latin America where Washington has not regained the position it lost" in the 2000s, Seman added.
With President Donald Trump in the White House, "strongmen have the edge" in US foreign policy, said US analyst Michael Shifter.
Bolsonaro's triumph however raises fears of a return to authoritarian rule in a region which has suffered under a string of military dictatorships.
The shift will be stark, according to Mark Weisbrot of the Center for Economic and Policy Research in Washington.
"This is a guy who said the Brazilian dictatorship didn't kill enough people, that they need to kill another 30,000 people, that the police should be able to kill suspects, that the left will have a choice of going to jail or leaving the country.
"Will he do these things? I think he will implement as many of these threats as he can get away with," said Weisbrot.
'Not so extreme'
However, "the shift towards authoritarian rule may not be as extreme as many fear," according to Shifter, head of the Inter-American Dialogue think tank - because traditional parties in Congress could yet provide checks and balances.
There could be a "modest Bolsonaro effect" in neighbouring countries, especially those that experienced military rule, "but each country has its own particular dynamics that shape its political direction. Any contagion would be limited."
Ivan Briscoe, Latin America director of the International Crisis Group, said the ex-soldier's rise is part of a gradual "winnowing of democracy" in the region, the most notable examples being Venezuela and Nicaragua.
Bolsonaro wielding power in the volatile social context of Brazil is alarming.
"When you have a populist authoritarian, militaristic ruler in that context, he isn't just a laughing stock - as Trump often is - he is actually a very serious challenger to civil rights, and human rights and basic freedoms."
Bolsonaro has much in common with Mexico's president-elect Andres Manuel Lopez Obrador, said Briscoe.
"It's the appeal of the strong leader, it's the slightly vague political program, it's the promise of 'trust me, I will do the job' - it's the style. So we might see similar campaigning in Latin America."
Bolsonaro's trade choices
Bolsonaro has vowed to implement free-market reforms in the region's biggest economy and recently accused China - its largest trading partner - of "buying Brazil."
Beijing is set to build on its aggressive strategy in the region in recent years, analysts agree, with a style that appeals to Latin American leaders.
"It provides much more direct investment, loans, and aid to developing countries than the US does, and has a policy of non-interference in the internal affairs of the recipients," Weisbrot pointed out.
Regardless of his China trade policy, it's an anxious moment for the struggling regional MERCOSUR bloc -- Brazil, Argentina, Uruguay and Paraguay.
"If Bolsonaro follows through on his idea of allowing members to pursue bilateral trade agreements, and not as a bloc, that would be a big blow," noted Shifter.
According to Weisbrot, Bolsonaro will "follow Macri and the other right-wing governments in pursuing commercial policies that the Trump administration favours."
Briscoe agrees that a leader with a "Brazil First" approach "is possibly not going to do wonders for MERCOSUR."
Worst case scenario
Regardless of Bolsonaro's appeal to the markets, Shifter says that based on his campaign rhetoric and background, we can expect "considerable erosion of democratic norms and institutions".
That means Bolsonaro supporting "right-wing and fascist movements everywhere, and also (being) a strong supporter of the Trump administration's foreign policy, which seeks to get rid of the remaining left governments," said Weisbrot.
The worst case scenario is that he could become South America's answer to the Philippine President Rodrigo Duterte, whose war on drugs has been credited with killing some 20,000 people since July 2016.
In a country where police killings number around 5,000 a year, "if Bolsonaro and all his deputies are saying 'the gloves are off, you can do what you want, we'll protect you, the courts won't prosecute you,' the signal which will be given in that context could lead to appalling violence," said Briscoe.
"In Brazil it really is a risk."