Taxpayers cannot challenge a White House initiative that helps religious groups get federal funds for social programmes, the US Supreme Court says.
The ruling tightens limits on US students' free speech rights
The justices ruled by 5-4 that a group called Freedom From Religion Foundation had no legal right to bring the case.
The group had objected to government conferences held to encourage religious groups to apply for federal grants.
The ruling did not address whether the scheme violates the constitutionally required church-state separation.
The White House's Office of Faith-Based and Community Initiatives was set up soon after George W Bush became president in 2001.
It was designed to help religious and community groups better compete for federal funds for programmes tackling problems such as poverty, substance abuse and homelessness.
'Parade of horribles'
The Freedom From Religion Foundation said officials for the group violated the constitution by holding conferences which favoured faith-based groups over secular ones.
The foundation's lawsuit was based on a 1968 Supreme Court ruling that allowed taxpayers to challenge the government over programmes promoting religion in schools.
But government lawyers successfully argued that the precedent allowed challenges only if the programme in question was funded by a specific bill in Congress.
The funding for Mr Bush's faith-based social programmes came from a White House discretionary fund.
Giving the majority ruling, Justice Samuel Alito said the group had "set out a parade of horribles that they claim could occur" if the faith-based initiative were not stopped.
"Of course none of these things has happened," he wrote, adding that Congress could quickly step in if there were a problem.
White House spokeswoman Emily Lawrimore said the ruling was "a substantial victory for efforts by Americans to more effectively aid our neighbours in need of help".
The Rev Barry Lynn, of the group Americans United for Separation of Church and State, said the decision was disappointing but would not prevent other cases being brought.
"Taxpayers should be allowed to challenge public funding of religion, whether the money is allocated by Congress or the White House," he said.