Juan Guaidó, head of the Venezuelan National Assembly and lawmaker of the opposition party Popular Will, gestures as he arrives at a gathering in La Guaira on Jan. 13, 2019. (Carlos Garcia Rawlins/Reuters)

Editor’s note: A version of this article first appeared on Jan. 14. It has been updated.

Earlier this month, few outside of Venezuela knew of Juan Guaidó. But the 35-year-old industrial engineer has suddenly emerged as a cause celebre, heralded by global leaders for his challenge to the near-total President Nicolás Maduro.

Following May elections internationally derided as a fraudulent power grab, Maduro was sworn in for a new six-year term on Jan. 10. One day later, Guaidó — the head of the opposition-controlled National Assembly — took a step Venezuelan critics had long considered too dangerous: invoking articles in the constitution that allow the head of the assembly to assume national leadership if a “usurper” takes office.

On Wednesday, hundreds of thousands of Venezuelans poured into the streets in planned protests to demand Maduro’s ouster. That day, Guaidó took the ultimate step and declared himself “president in charge” and the legitimate leader of the country. The Trump Administration and a host of other governments immediately recognized him as such.

“We will stay on the street until Venezuela is liberated!” Guaidó told a crowd in Caracas that day.

Maduro is not going quietly, if at all. He has reasserted his claim to the presidency and ordered the expulsion of U.S. diplomatic personnel — a directive the Trump administration has refused to comply with fully. He also garnered public support from long-time allies Russia and China, among others. But in a socialist country buckling under the weight of corruption, mismanagement and hyperinflation that has left food and medicine scarce, the relatively unknown, inexperienced Guaidó has energized the moribund opposition.

Guaidó’s Twitter bio describes him simply as a “public servant” who is “in love with Venezuela.” He has held one public post when he was elected legislator for the state of Vargas, in 2015. Before that, he was part of a student movement that protested then-President Hugo Chávez in 2007.

The son of a commercial pilot and teacher, Guaidó grew up in a middle-class family, one of eight children. His mentor, Leopoldo López, founded the Popular Will party in 2009 and led a wave of protests in 2014 before being jailed. He is still under house arrest.

“Obviously Guaidó is not the seasoned veteran that other politicians are, but that can actually work in his favor,” said David Smilde, senior fellow at the Washington Office on Latin America. “He doesn’t have the old backdoor political culture, and he brings something different.”

Guaidó inherited the top post at the Popular Will party, partly because most of its leadership has been jailed or fled the country. On Jan. 5, he was named the head of the opposition-controlled National Assembly, which maintains broad recognition internationally despite having been stripped of its powers by Maduro in 2017.

On Jan. 13, Guaidó was on his way to a rally just outside Caracas when he was intercepted by the intelligence police, forced into a van and detained for about 45 minutes. He was released unharmed, but his detention showed how dangerous his bid to oust Maduro had become. It also showed how quickly he had captured the public’s imagination: In just one day, he tripled his Twitter followers — from 100,000 to 334,000.

His detention followed arguably the most radical step the country’s opposition had taken since Maduro rose to power in 2013, succeeding the leftist firebrand Chávez, who died of cancer that year. Violent repression of protests in 2017 led to the deaths of more than 100 people. Since then, the opposition has fizzled.

Guaidó, however, began to gain traction. Chile and Colombia expressed support for the National Assembly. The head of the Organization of American States, Luis Almagro, and Brazil’s new far-right president, Jair Bolsonaro, effectively recognized Guaidó as Venezuela’s interim president, even though he had not yet claimed that mantle himself.

In a tweet the same day Guaidó was detained, Vice President Pence and national security adviser John Bolton condemned the arrest and praised what they called his “courageous decision” to challenge the authority of Maduro, whom they denounced as “illegitimate.”

In a televised address after Guaidó first raised the possibility of replacing Maduro, Maduro called Guaidó’s move “a show” and said a group of “little boys” had taken over the opposition. “This Guaidó, people will ask, who is that?”

Some today may also be asking that question, but for a very different reason.