Supreme Court Justice Anthony Kennedy was nominated by President Ronald Reagan and confirmed in 1988. A look at his key opinions,

Anthony Kennedy has been a key — even swing vote — on high-profile issues including gay rights, abortion, affirmative action and campaign finance. Here’s a sampling of his opinions:

Obergefell v. Hodges

(2015): In a landmark gay marriage decision, Kennedy wrote for a divided court that same-sex couples have the right to marry anywhere in the United States.

The ruling meant that states could not enforce bans on same-sex marriage. It also held that the Constitution’s promises of due process and equal protection guaranteed the right of gay couples to marry without legal barrier.

United States v. Windsor

(2013): Obergefell was hardly Kennedy’s only significant gay-rights opinion.

He wrote a 2003 opinion that invalidated Texas’ law against sodomy. Ten years later, Kennedy wrote a landmark decision that struck down a key section of a federal law that kept legally married same-sex couples from receiving tax, health and pension benefits.

The case concerned a section of the federal Defense of Marriage Act that barred same-sex couples from collecting federal marriage-related benefits.

In an opinion joined by the court’s four liberal justices, Kennedy said the primary effect of the law was to “identify a subset of state-sanctioned marriages and make them unequal.”

Citizens United v. FEC

(2010): In arguably the most significant campaign finance ruling in the court’s history, Kennedy wrote the 5-4 opinion that opened the door to greater political spending by independent groups. The opinion removed caps from independent spending by corporations and labor unions.

Roper v. Simmons (2005): Kennedy wrote multiple notable opinions on capital punishment, including this ruling that it is unconstitutional to execute defendants for crimes committed when they were younger than 18.

The case concerned a gruesome Missouri murder and a 17-year-old defendant, Christopher Simmons, who was convicted along with a friend of kidnapping a woman from her home and throwing her body over a bridge and into a river.

Simmons was sentenced to death. But Kennedy held that it violated the Eighth Amendment’s prohibition against “cruel and unusual punishment” to execute people for crimes committed as juveniles.