LOUISVILLE – A remarkable experiment in school desegregation has thrived for four decades in this Kentucky city and its suburbs, surviving fierce resistance from the Ku Klux Klan and a legal defeat at the U.S. Supreme Court.

Even as integration efforts faded across much of the South and schools nationwide have grown more segregated by race and class in recent years, Jefferson County persisted in using busing and magnet programs to strengthen diversity in the classroom.

White and black and poor and rich children share schools to a greater extent here than in most large districts across the country, leading to friendships across the usual social divides and giving rise to what school officials say are stronger academic outcomes for disadvantaged students.

Now, the program is in danger of being dismantled.

The threat is no longer from protesters in hoods throwing bricks at buses carrying black kids into white parts of town, but from state legislators pushing a bill to require a return to neighborhood schools. The measure underscores the historic tension between the dueling ideals of classroom diversity and close-to-home education.

If enacted, the bill would deeply shake the Jefferson district, by far the largest in Kentucky, with 101,000 students in 155 institutions.

“This is a bill that will resegregate our schools, taking us back to the ’60s and ’70s,” said Chris Kolb, a graduate of Jefferson schools and a member of the county school board, which opposes the measure. “This will be the death of integration.”

Kentucky’s House of Representatives, with a new GOP majority, passed the bill last month 59 to 37, with every Democrat and one Republican opposed. It is now pending in the GOP-dominated Senate, which passed similar measures twice in recent years. A spokesman for Gov. Matt Bevin (R) did not respond to a question about whether he supports the bill.

State Rep. Kevin D. Bratcher, sponsor of the bill, said it aims to bring common sense to a system that is unfair to children who can’t get into schools around the corner or across the street from where they live. Bratcher, who is white and represents part of Jefferson County, said he’s sensitive to concerns about resegregation.

“But we have to look at what we’re giving up for desegregation,” he said. It’s harder for children in faraway schools to participate in extracurricular activities, he said, and for their parents to make it to PTA meetings and teacher conferences. What’s more, he said, busing costs student time and taxpayer money that could be better spent.

Bratcher cited his own experience in a county high school in the 1970s, when he was forced to leave his neighborhood and take a bus to a historically black school 45 minutes away. “Sending a child to a school just right down the street is a powerful benefit,” he said.

Many in Louisville, a Democratic stronghold, chafe at the notion that Republicans – known as the party of local control – want to override the wishes of local officials. Not only does the school board support desegregation via busing, but voters in board elections have consistently rejected candidates who pledged a return to neighborhood schools.

“Local control as a principle goes out the window at convenience,” said Raoul Cunningham, president of the NAACP’s Louisville chapter.

Two-thirds of the district’s students come from low-income families. Nearly half are white, 37 percent are black and 9 percent are Hispanic.

The vast majority of schools meet the district’s diversity target. Fewer than 15 percent of students attend a school in which the total white or the total nonwhite students make up more than three quarters of enrollment, a Pennsylvania State University researcher found.

Under the bill, more than half of students in the district would be moved to a new school.

Opponents say that would wreak havoc, overcrowding some schools and leaving others half-empty. They also say the bill contradicts the Republican push for school choice.

Jefferson County long ago replaced the forced busing of the 1970s with a voluntary approach to integration, offering arts- and science-themed magnet programs to draw students into different parts of town.

The bill would effectively eliminate many of those programs by requiring the district to allow children to attend the school closest to their homes. Such a provision is race-neutral on its face, but the deeply segregated housing patterns in the sprawling county mean that a return to neighborhood schools is likely to concentrate poor and minority students in schools apart from their white, affluent peers.

Research shows that isolating poor children is an ill-advised strategy for schools looking to boost low-income learning. Jefferson schools still struggle with achievement gaps – 61 percent of white elementary students are proficient or better in reading, compared with 31 percent of black students and 43 percent of Latinos. But the district has found that children in poor areas who attend mixed-income schools outperform neighbors who go to high-poverty schools.

State Rep. Attica Scott (D), who is African American and represents part of Jefferson, was bused while growing up in the late 1970s and 1980s from a low-income, largely black housing development to a school in a predominantly white neighborhood. Then she attended a magnet high school with students from across the county.

“For me, it was this opportunity to be with kids who weren’t like me – to be able to develop those relationships and connections and to get to know each other in ways that would not have been possible without busing,” Scott said.

Although the system has flaws, Scott said, “I don’t believe we throw out this entire attempt of integrating.”