Venezuela’s best-known opposition leader, Juan Guaidó, has touched down in the United States after being unceremoniously ejected from Colombia while attempting to gatecrash a summit about the political future of his crisis-stricken homeland.

Guaidó shot to fame in early 2019 and for a brief moment looked poised to topple Venezuela’s authoritarian leader, Nicolás Maduro, with the support of dozens of foreign governments including the US, UK and Brazil.

But four years later the 39-year-old’s star has waned dramatically as a result of his failure to unseat Hugo Chávez’s political heir. Maduro has crushed street protests and consolidated power. Most of the international community has abandoned Guaidó’s parallel “presidency” and “interim government”.

And key regional powers such as Colombia and Brazil have elected leftist leaders who have revived ties with Maduro’s administration and condemned Guaidó’s attempt to bring it down by using foreign pressure to spark a military uprising.

Late on Monday, Guaidó announced he had crossed into Colombia on foot to escape Maduro’s “persecution” and attend an international summit which Colombia’s president, Gustavo Petro, is hosting, in an effort to solve Venezuela’s deeply entrenched political crisis.

However, hours later Guaidó was removed from the South American country by migration officials and boarded a plane to the US, where he landed early on Tuesday. “Unfortunately, the persecution of the dictatorship spread to Colombia today,” he said in a video statement filmed inside.

“Guaidó didn’t say it, but everything suggests he will not return to Venezuela,” Luz Mely Reyes, a prominent Venezuelan journalist, tweeted as the politician touched down in Miami.

Christopher Sabatini, a Latin America specialist from Chatham House in London, said Colombia’s decision to send Guaidó packing was a melancholy reflection of how dramatically his political standing had changed since early 2019, when he led huge protests through the streets of Caracas and enjoyed significant global support.

“It’s a sort of sad coda to his so-called presidency,” said Sabatini, who said he suspected Guaidó’s decision to travel to Colombia was a political stunt designed to reassert his waning authority over Venezuela’s opposition.

In fact, Sabatini said he believed Guaidó’s move – which he likened to a botched comeback attempt by the US actor Mickey Rourke – had merely highlighted his weakness. “It’s pure performance. He’s trying to make himself relevant again but it has the opposite effect. It makes him look sad.

“The truth is that most of the governments that are attending [Petro’s conference] – Spain, the UK, Chile and others – no longer recognize [Guaidó’s] government, such as it was, or are now engaging with the Maduro government,” Sabatini added.

“He’s become a little bit of a caricature, to be honest. [He has] no real authority, not much popularity. He is clearly trying to grab headlines and make himself relevant and engaging.” But this week’s drama had merely “reinforced the sense of his irrelevance”.

Guaidó continues to insist his crusade to bring political change to Venezuela is alive.

Before leaving the country, he had planned to take part in October opposition primaries designed to select a candidate to challenge Maduro in a presidential election scheduled for next year. That will be the first such vote since the 2018 election which Maduro won despite leading his country into one of the worst economic collapses outside a war zone in recent history. Much of the international community denounced the 2018 election as an undemocratic sham.

Guaidó’s party, Voluntad Popular (Popular Will), condemned what it called his “arbitrary expulsion” from Colombia.

However, Petro pushed back, claiming his country would have “gladly” offered Guaidó asylum had he arrived at an official port of entry and presented a passport.

“There is no reason to enter the country illegally,” Colombia’s leftist president tweeted.

“Clearly, a segment of politics wanted to disturb the unhindered progress of the international conference on Venezuela,” Petro added.

At the opening of his one-day conference on Venezuela, Petro said he wanted to see steps to ensure its citizens were free to democratically elect their leaders. But Colombia’s president also called for an end to US sanctions which he blamed for the dire humanitarian crisis that has forced more than seven million Venezuelans to flee abroad over the past eight years.

“We have seen it on our streets​: [Venezuelan] ​p​eople going hungry on the streets of Bogotá and Colombia. People fleeing hunger, fleeing misery​,” Petro told diplomats from countries including the US, Germany, Mexico, South Africa, the UK and Brazil.

“​​The ​America​s​ cannot be a place of sanctions. ​The Americas must be a place of freedoms. ​And the Americas must be a place of democrac​y.”