And there were, predictably, rules governing how Summer dressed. Carver Collegiate’s coed code called for khaki pants pulled up to the hip; a black or brown leather (or imitation-leather) belt; a school-issued polo shirt with the collar turned down; a white or black undershirt; and no hats, sunglasses, sparkles, flash, or bling of any kind. Students could be barred from class for wearing the wrong kind of shoe, such as the popular Air Jordans; the code mandated specific colors, styles, and brands, Adidas and Chuck Taylor among them.

Summer was a high-school freshman, 14 years old. “It felt like I was in elementary school,” she said, where in fact she had had it easy by New Orleans standards: she’d been spared the silent lunches and embarrassing punishments her peers at some other schools had endured. At Carver, Summer quietly rejoiced whenever she discovered a way to assert her individuality without breaking code, like wearing purple lipstick.

Over the past two decades, hundreds of elementary and middle schools across the country have embraced an uncompromisingly stern approach to educating low-income students of color. But only more recently have some of the charter networks that helped popularize strictness, including the Knowledge Is Power Program (KIPP), opened high schools—an expansion that has tested the model in new, and divisive, ways. There’s no official name for this type of school, and not all of the informal terms please the educators in charge: the ethos is often described as “no excuses,” “paternalistic,” or devoted to “sweating the small stuff.” The schools, most of them urban charters, share an aversion to even minor signs of disorder and a pressing need to meet the test-based achievement standards of the No Child Left Behind era or else find themselves shuttered. Front and center in their defense of intensive regimentation for their predominantly minority students is a stirring goal beyond that bottom line: to send all their graduates, many of them first-generation college aspirants, on to higher education.

Yet a growing array of critics is concerned that the no-excuses approach more effectively contributes to very different results: a flagrant form of two-tiered education and a rise in racially skewed suspension and expulsion rates for low-level misbehavior—a trend that Secretary of Education Arne Duncan has railed against repeatedly over the past year. Some go further, arguing that those taped lines point the way to prison rather than to college—that the harsh discipline is a civil-rights abomination, destined to push too many kids out of school and into trouble with the law. For the families involved, particularly the students, the story is more complicated. Many of them come to appreciate the intense structure, but only if they also come to trust the mostly young educators who enforce it. As school leaders in New Orleans are discovering, forging that trust is far harder than teaching someone to say thank you and toe an orange line.

New Orleans schools, which have taken the experiment with paternalistic public education to a new extreme, have been at the forefront of extending regimented discipline to the high-school level. After Hurricane Katrina devastated the region in 2005, the city became a proving ground for the most popular and contentious reforms. The charter-school movement grew, spreading a heavy reliance on alternative teacher-recruiting programs like Teach for America—and, not least, a commitment to comprehensive, punitive discipline policies very different from the pedagogical flexibility and emphasis on individual expression favored by many traditional education schools.