In this paper, I apply Mettler's concept of the “submerged state” to aid for children at private schools in the United States, including education vouchers, in-kind aid, and property tax exemptions. All aid policies are “submerged” in that they help private organizations take on state functions but some are more submerged than others. Theoretically, this paper distinguishes between subcategories of submergence. Using policy data from 50 states and an original database of court challenges between 1912 and 2015, I employ probit regression with sample selection to evaluate the effect of submergence on successful court challenge. I find that more submerged policies are less likely to be successfully challenged than less submerged policies. Submerged policy design enables supporters to avoid legal as well as political challenge.