Proponents of school choice are looking for ways to make school choice that includes private and religious schools legally sound. This paper describes how a carefully designed plan for universal school choice would be consistent with key rulings of the United States Supreme Court and the Minnesota Supreme Court. The paper first describes the 1971 landmark case, "Lemon v. Kurtzman," otherwise known as the "Lemon test," and the three test issues that must be addressed. A model plan for universal school choice is then presented, which is based on the following tenets: (1) aid should not be granted directly to religious schools; (2) religious schools must benefit only through the independent choices of parents; (3) all schools--public, secular private, and parochial--must be allowed to participate; (4) funding for students attending religious schools would be no greater than for those attending nonreligious schools; and (5) additional state regulation of religious schools above current regulatory levels should be minimized. The paper ends with a speculation as to how the members of the United States Supreme Court (as of October 1993) would be likely to approach a universal school-choice case. (Contains 72 endnotes.) (LMI)