Planned Parenthood v. Casey (1992): Kennedy voted to reaffirm the right to abortion under the due process clause of the 14th Amendment.
Gonzales v. Carhart (2007): Kennedy wrote the majority opinion saying a federal law criminalizing late-term abortion did not violate Planned Parenthood v. Casey because it did not impose an "undue burden".
Boy Scouts of America v. Dale (2000): Kennedy voted to uphold the Boy Scouts of America's organizational right to ban homosexuals from being scoutmasters.
Romer v. Evans (1996): He wrote the court's opinion in the 1996 case that made unconstitutional a provision in the Colorado Constitution denying homosexuals the right to bring local discrimination claims.
District of Columbia v. Heller (2008): Kennedy sided with conservatives in striking down a ban on handguns in the District of Columbia.
United States v. Windsor (2013): Kennedy wrote the majority opinion saying that restricting federal interpretation of "marriage" and "spouse" to apply only to opposite-sex unions as spelled out in Section 3 of the Defense of Marriage Act (DOMA), is unconstitutional under the due process clause of the 5th Amendment.
Kennedy wrote, "The federal statute is invalid, for no legitimate purpose overcomes the purpose and effect to disparage and injure those whom the State, by its marriage laws, sought to protect in personhood and dignity. By seeking to displace this protection and treating those persons as living in marriages less respected than others, the federal statute is in violation of the Fifth Amendment."
Obergefell v. Hodges (2015): The court ruled that same-sex couples must be allowed to marry nationwide.
Kennedy wrote the opinion saying “No union is more profound than marriage, for it embodies the highest ideals of love, fidelity, devotion, sacrifice and family. In forming a marital union, two people become something greater than once they were.” Many have used that passage as part of their wedding vows.
Boumediene v. Bush (2008): Kennedy wrote the majority opinion that the constitutionally guaranteed right of habeas corpus applies to those held in Guantanamo Bay and those known as enemy combatants.
Florence v. County of Burlington (2012): The court ruled that people detained and admitted to jail for any offense may be subjected to strip searches without a reason to suspect contraband.
Lawrence v. Texas (2003): Kennedy wrote the majority opinion that struck down the anti-sodomy law in Texas in a 6–3 decision.