In a televised new year’s message to his atrophying nation, Nicolás Maduro struck an upbeat tone. “Victory awaits us! The future awaits us! And everything will be better!” Venezuela’s embattled president insisted, declaring 2019 “the year of fresh starts”.

But the sandbags and rifle-toting troops that now encircle the Miraflores presidential palace in Caracas suggest far less confidence about the days ahead, as Venezuela sinks deeper into economic ruin and political isolation and questions grow over Maduro’s future.

Hugo Chávez’s 56-year-old heir – narrowly elected after his mentor’s 2013 death and then again in disputed elections last May – will begin his second presidential term on Thursday, amid intensifying international condemnation of what critics call his illegitimate and authoritarian rule.

Last week, a regional bloc known as the Lima Group turned up the heat, with 13 of its 14 members announcing they would not recognise Maduro’s new six-year term and urging him to step down. Those countries included Brazil, whose new far-right president, Jair Bolsonaro, is well-known for his hostility to Maduro and whose pro-Trump foreign minister recently called for Venezuela’s “liberation”.

The US has also stepped up pressure ahead of what it calls Maduro’s “sham inauguration” with the secretary of state, Mike Pompeo, telling one Brazilian newspaper “several things” could be done to rid Venezuela of Maduro’s “unacceptable” regime. Pompeo did not specify what those “things” might be but the remark echoed Donald Trump’s thinly veiled threat that military action was possible if Maduro did not go voluntarily.

Despite the rhetorical war – Maduro recently ordered his troops to prepare to rip out the hearts of “imperialist” invaders – observers still consider a foreign military intervention unlikely.

“I don’t see boots on the ground,” said Matias Spektor, an international relations specialist from Brazil’s Getúlio Vargas Foundation.

But after years of dawdling, regional patience does appear to be running out, as the situation in Venezuela deteriorates and Latin American politics swerves to the right under leaders such as Bolsonaro, Colombia’s Iván Duque, Chile’s Sebastián Piñera and Argentina’s Mauricio Macri.

“The dynamics are changing and they are changing very fast,” said Spektor, calling the rise of those politicians decidedly bad news for Maduro.

Spektor said the Lima Group’s unexpectedly firm declaration – which includes plans for financial sanctions, preventing top Venezuela officials entering their countries, and suspending military cooperation – appeared partly designed to persuade the Venezuelan military to abandon their commander-in-chief.

“For the regime to collapse you need to get Maduro out of the country and you need to get the military to stop supporting the regime … The way you do that is by sending signals to the military that in the long run if they stick to Maduro and the regime they will lose power,” he said.

Latin American governments did not want regime change imposed by outsiders “because they know full well it would backfire – but they do want to see regime change via peaceful means”.

Under its new leftist president, Andrés Manuel López Obrador, Mexico has resisted joining the anti-Maduro offensive, a move decried by human rights activists and Venezuela’s opposition. “I don’t stick my nose into other countries’ affairs,” López Obrador said last week, emphasizing Mexico’s return to a foreign policy of non-intervention.

But most Latin American countries are moving in the opposite direction, leaving Maduro increasingly friendless in a region his Bolivarian predecessor, Hugo Chávez, dreamed of uniting during the “pink tide” era of leftist rule.

Brazil, in particular, looks poised to play a frontline role in the diplomatic push to force Venezuela’s president out. “In the early days of the administration, my understanding is that people in the Bolsonaro government want to send a very clear and unequivocal signal that Maduro’s costs in the region are about to go up,” said Spektor.

Brazil’s foreign minister, Ernesto Araújo, hinted at that harder line this week arguing: “You have to face the threats, and the main one comes from non-democratic regimes that export crime, instability and oppression. You can’t simply wish away dictatorships such as Venezuela and Cuba.”

Bolsonaro’s politician son, Eduardo, tweeted: “The noose is tightening around Nicolás Maduro.”

David Smilde, a Venezuela expert from the Washington Office on Latin America advocacy group, said there was a growing sense that with the end of Maduro’s first term and growing regional pressure the crisis was entering a new phase: “But nobody really knows just exactly what it amounts to.

“It’s one thing to say: ‘You’re illegitimate’. But how much does that mean in the end? It doesn’t look like any of the Lima Group members or the United States are going to close up their embassies or break off diplomatic relations,” he said.

“They want Venezuela to return to democracy in some way … [and to stop] the mass exodus of Venezuelans … but I don’t think they really have much of an idea how to do that.”

Maduro and his inner circle would be fretting over their increasing isolation “and that’s why you see them reaching out to the Russians and the Chinese continually”, Smilde said. But any international effort to engineer a peaceful transition would founder unless Venezuela’s fractured opposition united.

“Until that happens, the government can kind of do whatever it wants – even a weak government can consolidate if it has no opposition.”