(LAS VEGAS) — More than a third of U.S. states have created school voucher programs that bypass thorny constitutional and political issues by turning them over to nonprofits that rely primarily on businesses to fund them. But the programs are raising questions about transparency and accountability at a time when supporters are urging that they be expanded into a federal program. Unlike traditional school vouchers, which are directly funded by the states or in the case of Washington, D.C., the federal government, these programs don’t use any public money.