Justice Anthony Kennedy has shunned being called a "swing vote" on the grounds it falsely implies he's an activist judge purposely trying to pull the Supreme Court in one direction or the other. But regardless of motive, he has provided key votes in the majority of many landmark 5-4 decisions that have defined the court -- and helped shape national law -- during his 26-year tenure on the high court. Here are a few examples:

United States v. Windsor, 2013 — Ruled that the federal Defense of Marriage Act, a 1996 law that defined marriage as the union of a man and woman, was unconstitutional. While the decision didn't make gay marriage legal nationwide, it allowed states to establish their own pro-gay marriage laws. Kennedy wrote the majority opinion, saying the law "burdened" the lives of married gay couples. Social conservatives immediately accused him of being an "active judge," with broadcaster Pat Robertson suggesting Kennedy had "gay clerks" who influenced his decision.

Shelby County v. Holder, 2013 — The court struck down a key provision in the 1965 Voting Rights Act, a move that freed states of certain federal oversight of elections. The court left it up to Congress to draft new voting guidelines to ensure that states and cities with a history of voting discrimination properly follow the law.

District of Columbia v. Heller, 2008 — The court ruled that Americans have a constitutional right to keep guns in their homes for self-defense, the justices' first major pronouncement on gun control in U.S. history. The ruling struck down the District of Columbia's 32-year-old ban on handguns as incompatible with gun rights under the Second Amendment.

Gonzales v. Carhart, 2007 — In a case that upheld the Partial-Birth Abortion Ban Act of 2003, Kennedy wrote for the majority that the Constitution permits a nationwide prohibition on a specific abortion method. The court's liberal justices complained that the decision chipped away at abortion rights.

Roper v. Simmons, 2005 — The case abolished capital punishment for juvenile offenders. "From a moral standpoint, it would be misguided to equate the failings of a minor with those of an adult, for a greater possibility exists that a minor's character deficiencies will be reformed," Kennedy wrote in the majority opinion.

Bush v. Gore, 2000 — The ruling stopped a Florida recount of presidential ballots in the 2000 presidential election, effectively resolving the disputed contest that led to George W. Bush's victory over Al Gore.