RALEIGH, N.C. - The sprawling Wake County School District has long been a rarity. Some of its best, most diverse schools are in the poorest sections of this capital city. And its suburban schools, rather than being exclusive enclaves, include children whose parents cannot afford a house in the neighborhood.

But over the past year, a new majority-Republican school board backed by national tea party conservatives has set the district on a strikingly different course. Pledging to "say no to the social engineers!" it has abolished the policy behind one of the nation's most celebrated integration efforts.

And as the board moves toward a system in which students attend neighborhood schools, some members are embracing the provocative idea that concentrating poor children, who are usually minorities, in a few schools could have merits - logic that critics are blasting as a 21st-century case for segregation.

The situation unfolding here in some ways represents a first foray of tea party conservatives into the business of shaping a public school system, and it has made Wake County the center of a fierce debate over the principle first enshrined in the Supreme Court's 1954 decision in Brown v. Board of Education: that diversity and quality education go hand in hand.

The new school board has won applause from parents who blame the old policy - which sought to avoid high-poverty, racially isolated schools - for an array of problems in the district and who say that promoting diversity is no longer a proper or necessary goal for public schools.

"This is Raleigh in 2010, not Selma, Alabama, in the 1960s - my life is integrated," said John Tedesco, a new board member. "We need new paradigms."

But critics accuse the new board of pursuing an ideological agenda aimed at nothing less than sounding the official death knell of government-sponsored integration in one of the last places to promote it. Without a diversity policy in place, they say, the county will inevitably slip into the pattern that defines most districts across the country, where schools in well-off neighborhoods are decent and those in poor, usually minority neighborhoods struggle.

The NAACP has filed a civil rights complaint arguing that 700 initial student transfers the new board approved have already increased racial segregation, violating laws that prohibit the use of federal funding for discriminatory purposes. In recent weeks, federal education officials visited the county, the first step toward a possible investigation.

"So far, all the chatter we heard from tea partyers has not manifested in actually putting in place retrograde policies. But this is one place where they have literally attempted to turn back the clock," said Benjamin Todd Jealous, president of the NAACP.

School Board Chairman Ron Margiotta referred questions on the matter to the district's attorney, who declined to comment. Tedesco, who has emerged as the most vocal among the new majority on the nine-member board, said he and his colleagues are only seeking a simpler system in which children attend the schools closest to them. If the result is a handful of high-poverty schools, he said, perhaps that will better serve the most challenged students.

"If we had a school that was, like, 80 percent high-poverty, the public would see the challenges, the need to make it successful," he said. "Right now, we have diluted the problem, so we can ignore it."

So far, the board shows few signs of shifting course. Last month, it announced that Anthony J. Tata, former chief operating officer of the D.C. schools, will replace a superintendent who resigned to protest the new board's intentions. Tata, a retired general, names conservative commentator Glenn Beck and the Tea Party Patriots among his "likes" on his Facebook page.