For decades, the rational basis test seemed so deferential that no law could flunk it. In the 1980s, however, the Supreme Court began to give teeth to the standard. For example, in CLEBURNE V. CLEBURNE LIVING CENTER, INC. (1985), the Court used the rational basis test to strike down a Texas municipality's ZONING law that had been used to impede the creation of a group home for persons suffering from MENTAL ILLNESS.
By the 1990s, the rational basis test was no longer meek. It was explicitly used to invalidate state laws in two of the Court's most important CIVIL RIGHTS cases, HODGSON V. MINNESOTA (1990) and ROMER V. EVANS (1996). Hodgson was the first case in which Justice SANDRA DAY O'CONNOR voted to hold an ABORTION law unconstitutional. It dealt with a Minnesota law regulating the circumstances under which minors could obtain abortions; Minnesota required minors to get consent from both parents, rather than only from one. O'Connor joined an opinion by Justice JOHN PAUL STEVENS in which he concluded that Minnesota's two-parent consent was "not reasonably related to any legitimate state interest." Stevens reasoned that the two-parent consent requirement was likely to be important only in those cases where the two parents were not communicating with one another, and that requiring the minor to inform both parents under such circumstances was likely to do more harm than good.
Later, in PLANNED PARENTHOOD V. CASEY (1992), O'Connor co-authored an opinion that reaffirmed the existence
of a constitutional right to get an abortion, but formulated that right in terms of the "undue burden" standard. That standard is a kind of "reasonableness" test. It is arguably more akin to a strong rational basis standard than to STRICT SCRUTINY.
In Romer, the Court reviewed an amendment to the Colorado state constitution that prohibited the state or its local jurisdictions from protecting gay rights. Writing for himself and five others, Justice ANTHONY M. KENNEDY announced that Colorado's law failed to survive scrutiny under the rational basis test. Kennedy explained that "the amendment seems inexplicable by anything but animus toward the class that it affects" and hence "lacks a rational relationship to legitimate state interests."