Rehnquist cited "Roe v. Wade" and "Planned Parenthood v. Casey" in the opinion. The Court felt that the ban was rational in that it furthered such compelling state interests as the preservation of human life and the protection of the mentally ill and disabled from medical malpractice and coercion. It also prevented those moved to end their lives because of financial or psychological complications. The Court also felt that if it declared physician-assisted suicide a constitutionally protected right, it would start down the path to voluntary and perhaps involuntary euthanasia. Justice O'Connor concurred. Justices Souter, Ginsburg, Breyer, and Stevens each wrote opinions concurring in the judgment of the court. In 2008, Washington State voters approved 58%–42% the Washington Death with Dignity Act, which established guidelines for using the services of a physician to terminate one's life.