In 2005 in McCreary County v. ACLU, Sandra Day O’Connor tendered the decisive vote to hold unconstitutional a Kentucky courthouse’s Ten Commandments display, she asks: “Those who would renegotiate the boundaries between church and state must therefore answer a difficult question: Why would we trade a system that has served us so well for one that has served others so poorly?” She introduced the “endorsement test,” which reinforced the establishment clause principle that the government may not support a particular religious viewpoint and, instead, must endeavor to be neutral toward religion. Source: