Thousands of diehard Jair Bolsonaro followers have converged on Brazil’s political and economic capitals hoping to stage a colossal show of support for their beleaguered president amid mounting fears over the future of Brazilian democracy and of possible skirmishes with the government’s opponents. The rightwing nationalist, who recently warned Brazil could face a political “rupture”, is expected to address packed independence day rallies in Brasília and São Paulo on Tuesday in what observers say is an increasingly weak politician’s attempt to project strength. Bolsonaro’s approval ratings have plummeted in recent months as corruption allegations have ensnared a succession of allies and relatives and a congressional inquiry has savaged his government’s response to a Covid outbreak that has killed nearly 600,000 Brazilians. Polls suggest almost two-thirds of Brazilians now oppose Bolsonaro’s presidency and that the leftwing former president Luiz Inácio Lula da Silva would beat him in next year’s election. “These are the death throes of a government in agony,” Alessandro Molon, a congressman from the leftwing Brazilian Socialist party (PSB), said of Tuesday’s planned demonstrations. But Bolsonaro still enjoys substantial support, particularly among evangelical Christians and in Brazil’s agricultural heartlands and deep south. As they poured into Brasília from across the country, on buses, trucks and planes, those disciples said they were determined to champion a leader whose chances of re-election next year look increasingly frail. “Man, I feel immense happiness at being here because we’re here to make our country a better place and get these corrupt folk out,” said Orlandino Mendes Valentim, 54, who had driven 700 miles to the capital from the town of Mantena in the south-eastern state of Minas Gerais. “We thank God that a man like Bolsonaro came along to fight our corner,” Valentim said as he strolled through the political centre of Brazil’s futurist capital on Monday afternoon, past street vendors selling T-shirts depicting Bolsonaro wearing army fatigues and with the English slogan: “Make Brazil Great Again.” He added: “We don’t want to turn into some kind of Venezuela or Argentina.” Valentim’s travelling companion Custódio Marques Junior said he had come to fight for the future of his children and grandchildren and to make Brazil more like the US, where he is a citizen and has lived for many years. He brandished a bright yellow jersey stamped with the words: “Fechados com Bolsonaro.” (We’re with Bolsonaro.) “Tomorrow is about our freedom. It’s 7 September. ‘Independence or death!’” Marques said, quoting the cry attributed to the then prince regent, Dom Pedro, as he proclaimed Brazilian independence from Portugal in September 1822. Valentim insisted Tuesday’s rally on Brasília’s esplanade of ministries – the heart of government in Latin America’s largest democracy – would be peaceful. “Bolsonaro voters are people of peace,” he said. But there are growing fears there could be spasms of violence, as hardcore supporters of Brazil’s pro-gun president hit the streets. Before the demonstrations, one Bolsonarista extremist posted an online video from outside the supreme court in which he urged his president to use “gunpowder” against its “rotten” justices. There are particular concerns that in Brasília, rightwing radicals could clash with leftist demonstrators or thousands of indigenous activists who have been camped out near congress since last month to protest against efforts to roll back their land rights. Others fear Bolsonaro may seek to seize dictatorial powers by staging a self-coup or wonder if 7 September could turn out to be a Brazilian version of the 6 January assault on the US Capitol by extremist supporters of Bolsonaro’s political inspiration Donald Trump. Addressing a congress of Bolsonaro supporters in Brasília on Saturday, the former US president’s son Donald Trump Jr reportedly urged delegates to resist the imposition of “tyrannical governments”. Molon, the leftist congressman, said his party had advised members to stay at home to avoid violence that would give Bolsonaro a pretext to send in the army. “Bolsonaro needs chaos. He is the lord of chaos,” said Molon. “Confrontations or conflicts are all he desires so he can summon the armed forces.” Ruth de Aquino, a columnist for the newspaper O Globo, said she feared the president was deliberately seeking to spark “pandemonium” that would help him cover up Brazil’s bleak economic outlook, a severe energy crisis and his bungling of Covid. “Bolsonaro is trying to distract attention from this chaos by doing the only thing he knows: provoking chaos and upheaval,” she said. Supporters of Bolsonaro, a 66-year-old former army captain who won power in 2018 as part of an anti-establishment backlash, say such fears are overblown. “He’s a raging bull who might hurt you at first because he’s wild and you can’t tame wild animals. But he’s a bull we needed to unleash to shake this country up a bit,” said Elves de Sousa, a 41-year-old evangelical pastor who plans to join a pro-Bolsonaro rally in the midwestern city of Sinop. Sousa said corruption had become so deeply entrenched under past governments that only a radical figure such as Bolsonaro could set things right, despite the fact that Bolsonaro’s allies and sons have been implicated in a series of recent corruption scandals. “We needed a madman. With the greatest respect for our president, I think we needed someone like him, someone radical, to change this,” Sousa said. Molon said he had no doubt that Bolsonaro, who has publicly expressed admiration for authoritarians, including the former Chilean dictator Augusto Pinochet, harboured desires to do away with the democratic system that brought him to power. “He’s never hidden it from anyone.” But the congressman doubted Brazil’s president had the support to pull that off this week and believed Tuesday’s rallies were more a desperate attempt to project power Bolsonaro no longer enjoyed. “He’s doing this because he’s cornered. He has realised that the near future holds electoral defeat and jail, for him and his sons,” Molon said. “It’s the reaction of a cornered animal.”