Baylson concluded that the district's plan was "narrowly tailored" to meet "race-neutral compelling educational interests," which included having two equally sized high schools, minimizing travel time and costs, maintaining educational continuity and fostering students' ability to walk to school.
The judge said the district's "mere consideration" of the racial makeup of the plaintiffs' neighborhood did not render the plan unconstitutional and thus the plaintiffs were not entitled to any relief on their claims.
Lower Merion Superintendent Christopher McGinley and school board president David Ebby said in a statement that the district was "pleased" with the decision.
James Herbert, a spokesman for the plaintiffs, said, "We're reviewing the decision carefully and considering our next steps."
The case stemmed from a lawsuit filed in May 2009 by plaintiffs who alleged that the plan discriminated against them and that their neighborhood was carved out for redistricting because it has a significant black population.
The district said its plan was based on the goal of equalizing the number of students who attend both high schools, and on elementary- and middle-school feeder patterns.
At a court hearing earlier this month, Baylson all but tipped his hand when he said that although race was a factor "motivating" the district's consideration of a plan, it was just one of many factors.
After Baylson made findings of fact in the case in May following a nine-day bench trial in April, he asked attorneys to file briefs (and later heard oral argument) on how a 2007 landmark U.S. Supreme Court decision - Parents Involved in Community Schools v. Seattle - affected the Lower Merion case.
Plaintiffs' attorney David G.C. Arnold had cited Seattle in support of plaintiffs' position, which held that school districts in Seattle and Louisville violated the U.S. Constitution's Equal Protection Clause by using a student's race to determine what high school he or she would attend.
But Baylson noted in his ruling yesterday that in contrast to the student-assignment plans in Seattle, where students were assigned to high schools on the basis of race, Lower Merion School District "assigned students to either Harriton High School or Lower Merion High School by neighborhood."
The judge said the Supreme Court has "never prohibited a school district from taking into account the demographics of a neighborhood," or even race, as one of many factors in assigning students to schools.
Baylson found the district's plan would have been adopted even had racial makeup not been considered.
He concluded that the evidence at trial showed that the district assigned particular neighborhoods, including South Ardmore, to attend Harriton High School, and "all students in those neighborhoods, both those who were African American and those who were not, lost their choice of high school."