When she changed her teaching plan and read a poem by the Cuban writer Nicolás Guillén, the students steered the conversation to the issue of the day. "I tried to avoid the subject of immigration but the students kept bringing me back to it," she told a local paper, the Newspaper Tree.
The next morning the school television channel showed a news clip of school walkouts in Los Angeles, Austin and Dallas. "The students went wild," says Sotelo, who is now under investigation for disrupting school activities for urging her students to leave school. "The administration quickly got on the intercom, instructing the teachers to turn off the television. But by then it was too late."
Around 700 El Paso students walked out that day. In predominantly Hispanic schools throughout the country, the story was the same. An estimated 70,000 walked out in San Diego county; in Los Angeles county 35,000 students left school over the course of the protests; in Dallas about 3,500 demonstrated. While some briefly stormed city hall, others stood outside chanting "Viva Latinos, viva Mexico".
The urge to ridicule young people's views is irresistible to some at the best of times, let alone when they leave their classes and take to the streets to challenge the government. "These kids don't know anything," one commentator told Bill O'Reilly, of Fox News. Several congressmen branded them truants, apparently unaware of how much more difficult it would be to stay in school if they or their parents were deported as the legislation suggested.
But while young people's political actions are easy to disparage, they are increasingly hard to dismiss, not just in the US but globally. For whatever else these youngsters may have learned in class, they clearly know enough to bring governments to the negotiating table and wrest major concessions from them when they get there.
The last few weeks saw more than 600,000 school students skip classes in Chile to demand free public transport, lower fees for college entrance exams and greater participation in government. On all three counts they were at least partly successful. The recently elected socialist president, Michelle Bachelet, offered an extra £104m for transport, some free lunches, mostly free entrance exams and the renovation of dilapidated buildings. She also set aside 12 of 74 seats on an advisory panel on education. After initially rejecting the offer, the students accepted the deal on Friday.
Meanwhile in France, over the past six months, two episodes of revolt - one of minority youth in the inner cities and the other of students and youth in the city centres - produced concrete results. After the former, last November, the government unveiled a raft of measures to tackle inner-city deprivation. During the latter, which saw two-thirds of universities occupied, blockaded or closed, hundreds of schools taken over and between one million and 3 million people in the streets, the government retracted an unpopular employment law.
These demonstrations were in no way connected. Yet between them - and countless others over the past few weeks, from pro-reform students in Iran to 4,000 youngsters in Slovenia - they suggest a surge of consciousness and activism among young people that goes beyond the immediate, local demands of each protest.
May '68 it isn't, although not for the reasons some of the leaders of that iconic student uprising would have you believe. Wistful for the days when you could picket an embassy, occupy your college, throw some cobblestones at the police and still have change left out of a fiver, many of those who rioted in 1968 have so gorged themselves on nostalgia that they have nothing but condescension and bile for young demonstrators who were born after that year.
"Young people [now] have a negative vision of the future," said Daniel Cohn-Bendit, one of the leaders of the Paris protests almost 40 years ago. "May 1968 was an offensive movement with a positive vision, but today's protests are all against things. They are defensive, based on fear of insecurity and change."
They conveniently forget that what followed their protests was a victory for Richard Nixon and increased representation for the Gaullists, who were instrumental in unleashing the forces that would produce the fear in the generations to come.
The people involved in the demonstrations today are in general younger, poorer and darker than those of 40 years ago. Young women are more likely to take a leadership role; their parents are more likely to support them. These are not middle-class students seeking an alliance with the workers; they are working-class students seeking passage to the middle class. In Chile, 87% of the public supported them. "These are not crazy revolutionaries," wrote Patricio Fernandez, an influential columnist in the Clinic newspaper. "Their parents support them. Their cousins, their neighbours, their old aunts. They are bored that the wealthy schools educate those who will be boss while their school trains them to be workers. More than combating Chilean authorities, they are convincing them."
While the conditions that produced these protests are particular, they are all underpinned by a common condition - the collapse of a postwar consensus where the state felt it had a role in investing in the futures of young people rather than at best neglecting and at worst criminalising them with everything from Asbos to curfews.
Take the US. In 1994, Clinton introduced a bill that allowed more juveniles to be tried as adults; between 1984 and 1997 the arrests of juveniles leapt 30%. Meanwhile, in the press, youngsters were being demonised in a similar manner to the Asbo culture in the UK. "Superpredators arrive," announced a Newsweek story in 1996 with the question: "Should we cage the new breed of vicious kids?" By 1998, two-thirds of Americans believed that children under the age of 13 should be tried as adults.
Whatever the gains of the 1968 student revolts - and there were some - it has been the generation forged in the crucible of those times who are responsible for these circumstances.
"Youth," wrote the German playwright Bertolt Brecht, "is when you blame your troubles on your parents; maturity is when you learn that everything is the fault of the younger generation."
· Gary Younge is the author of Stranger in a Strange Land: Encounters in the Disunited States.