But since Mr. Guaidó doesn’t control the country — Ms. Zubillaga can’t even get her Venezuelan passport renewed — his envoys operate in a diplomatic gray zone. Many have day jobs. The representative in Sweden teaches at a business school. The one in Israel is a rabbi. They’re typically well-educated Venezuelans who can afford to live in far-flung countries.

“So far we have been working as volunteers,” she said. “I pay for everything myself. There is no budget.”

The envoys’ status depends on the context. Mr. Guaidó’s emissary In Washington, Carlos Vecchio, is recognized as ambassador and — following a standoff — now has possession of the embassy. Ms. Zubillaga is “Madame Ambassador” among the Lima Group of Latin American nations and Canada. But the French government calls her a “special envoy” because — despite recognizing Mr. Guaidó as president — they consider Mr. Maduro’s appointee to be the ambassador. (This lets France “dialogue with all the actors of this crisis” to press for a peaceful transition and get humanitarian aid into the country, a diplomatic source said.)

Many of Mr. Guaidó’s diplomats are exiles themselves. Ms. Zubillaga fled Venezuela in 2014 after she and her family were subject to a violent home invasion and the country’s second-in-command, Diosdado Cabello, called her a terrorist on TV. Mr. Cabello is accused by the United States of drug trafficking and of running a vast network through which he embezzles and launders state funds.

“We had friends who were in jail, who were killed,” she told me. “I woke the kids at 5 o’clock in the morning, it was still dark, and I said, ‘We’re not going to school today, we’re going to New York.’”

They later moved to Madrid, where Ms. Zubillaga had a part-time job with an organic olive oil company, and eventually got a Spanish passport. At night she worked for the Venezuelan opposition, speaking to families of political prisoners. She added that the now-vast Venezuelan diaspora — the number of Venezuelans in Spain alone has doubled to 320,000 in the past four years — gives crucial support, too.

Since Ms. Zubillaga was familiar with France — she has a master’s degree from the Sorbonne — she began representing the opposition here. She points to diplomatic progress: As an opposition representative in 2014, she entered the Ministry of Foreign Affairs though the back door. In 2018, she was part of a delegation received publicly by President Emmanuel Macron. Now as “special envoy” she meets regularly with members of Mr. Macron’s foreign policy team.