WASHINGTON — The Supreme Court handed a surprising victory to the Obama administration and civil rights groups on Thursday when it upheld a key tool used for more than four decades to fight housing discrimination.

The justices ruled 5-4 that federal housing laws prohibit seemingly neutral practices that harm minorities, even without proof of intentional discrimination.

Justice Anthony Kennedy, often a swing vote, joined the court’s four liberal members in upholding the use of so-called “disparate impact” cases.

The ruling is a win for housing advocates who argued that the housing law allows challenges to race-neutral policies that have a negative impact on minority groups. The Justice Department has used disparate impact lawsuits to win more than $500 million in legal settlements from companies accused of bias against black and Hispanic customers.