In 2012, the U.S. Supreme Court ended one historic constitutional debate and stepped into another.

The justices created blockbuster bookends to the year when they upheld the nation’s new health care law after an extraordinary three days of argument in March, and when they agreed in December to hear one of the most important civil rights challenges in a generation, involving same-sex marriage.

The court defied predictions by many experts that it would strike down the Patient Protection and Affordable Care Act — the signature domestic achievement of the Obama administration. A 5-4 ideologically divided vote, those predictions said, would thrust the court into the presidential election.

However, Chief Justice John Roberts Jr., joining his four liberal colleagues for the first time in a 5-4 split, upheld the act’s core requirement, the so-called individual mandate to purchase insurance, as a constitutional exercise of Congress’ taxing power. The bipartisan ruling eliminated the possibility that the court would be a contentious election -year issue and avoided a confrontation with the administration.

There were more surprises in that mammoth challenge. Roberts and his four conservative colleagues adopted a new limit on Congress’ commerce clause authority. The individual mandate exceeded the lawmakers’ commerce powers because it sought to regulate “inactivity” and not “activity.” That distinction was successfully championed by Randy Barnett of Georgetown University Law Center and others. Also surprising, justices Stephen Breyer and Elena Kagan moved to the right in voting with their five conservative colleagues to find that the act’s expansion of Medicaid coverage unconstitutionally coerced the states into participating in the program. Not so surprising was that the court’s four conservative justices — Antonin Scalia, Anthony Kennedy, Clarence Thomas and Samuel Alito Jr. — would have struck down the entire 2,000-plus-page law because of the individual mandate.

While the health care decision (National Federation of Independent Business v. Sebelius) defined the Roberts Court in 2012, there were other significant and memorable court-related actions.

LEAKY SHIP

The Supreme Court has long been known as one government institution that does not leak — until this year. Soon after the court issued its ruling in the Affordable Care Act cases, Jan Crawford of CBS News cited unnamed sources “with specific knowledge of the deliberations” to report on internal conflicts over the decision. She said Roberts initially voted to strike down the “individual mandate” provision of the Affordable Care Act, but later decided to uphold it under the taxing power of Congress, infuriating conservative colleagues. Through the summer, several justices discounted the notion of serious rifts on the court. “No, I haven’t had a falling out with Justice Roberts,” said Scalia in a CNN interview.

PULLING RANK

The health care case was one of two politically charged sets of arguments considered by the justices in 2012. The court also took up the United States’ challenge to Arizona’s tough anti-immigration law. In a 5-3 decision, Kennedy, joined by Roberts, Ruth Bader Ginsburg, Breyer, Sonia Sotomayor and Kagan, held that three of four provisions in the law were pre-empted by federal immigration law, but that it was too early to say whether the fourth provision clashed with federal law. That provision requires officers who conduct a stop, detention or arrest in some circumstances to verify the person’s immigration status with the federal government.

NEW FAÇADE

Just in time for the beginning of the court’s new term, workers in late September placed a fabric screen called a “scrim” in front of the scaffolding that surrounds the court’s front façade as part of its marble repair project. Imprinted on the fabric was a full-sized photo of the pre-scaffolding façade, so that the passing public saw a representation of the same majestic marble and bronze front that has symbolized the high court since it opened in 1935. The representation was so real that many passersby did not even notice it as a change. Why conceal the scaffolding in this way? A court spokeswoman explained, “The scrim allows the building’s iconic façade to remain visible to tourists and visitors during cleaning and restoration work.”

JUVENILE MURDERERS

The justices have been re-examining the treatment of juveniles in the criminal justice system in recent years, and 2012 brought another major change. Kagan took the lead in a 5-4 decision holding that the Eighth Amendment prohibits the sentence of life in prison without parole for juveniles who commit homicides. Miller v. Alabama, together with Jackson v. Hobbs, was Kagan’s first significant majority opinion and was assigned to her by Kennedy.

CLERK POWER

After a history-making year at the nation’s highest court, last term’s Supreme Court law clerks were offered jaw-dropping hiring bonuses of $280,000 or more by law firms specializing in high court advocacy. With associate salaries at $150,000 or more at many large firms, that amounted to a first-year investment approaching $500,000 per law clerk, not counting other bonuses or benefits. Put another way, clerks were earning more than twice the salaries of the justices they worked for — even though ex-clerks are ethically barred from doing Supreme Court work for two years.

GPS EVIDENCE

Moving cautiously into privacy issues raised by new surveillance technology, the Supreme Court ruled unanimously that when law enforcement agents place a GPS device on a suspect’s car, it constitutes a “search” under the Fourth Amendment. But justices divided over the rationale, and the court stopped short of ruling that such a search would always require a warrant. The decision in U.S. v. Jones stemmed from GPS surveillance, for 28 days, of a car registered to the wife of Antoine Jones, a suspected drug dealer in D.C. The FBI search linked Jones to a “stash house” in Maryland that led to his arrest, conviction and life sentence. The January 23 ruling prompted the FBI to halt some of its GPS searches and to re-examine its surveillance practices.

STOLEN VALOR

By a 6-3 vote, the Supreme Court struck down the Stolen Valor Act, which made it a crime to falsely claim having won a military award or honor. Xavier Alvarez, a local California public official, was prosecuted under the law after he said he was a Medal of Honor winner at a public meeting. Writing for the court, Kennedy said that upholding a law targeting falsity on only one subject would give government license to “compile a list of subjects about which false statements are punishable.” The ruling followed a line of recent First Amendment cases in which the court has struck down restrictions on unpopular expression ranging from protests at military funerals to depictions of animal cruelty. Both houses of Congress responded to the June 28 ruling by passing differing bills that would outlaw claims of military honors, not just in the abstract, but for financial gain.

STRENGTH IN NUMBERS

All four women who have served on the U.S. Supreme Court joined for a discussion at D.C.’s Newseum in April. The event, sponsored by the Supreme Court Historical Society, honored retired Justice Sandra Day O’Connor on the 30th anniversary of her first term on the court. “This is fabulous to have all these women on the court!” O’Connor exclaimed. O’Connor and current members Ginsburg, Sotomayor and Kagan lamented the polarization of the Senate confirmation process since 1981, when O’Connor was approved, 99-0.

DUELING JUDGES

Scalia and Richard Posner, a judge on the U.S. Court of Appeals for the Seventh Circuit, engaged in a running feud after Posner authored a critical review of Scalia’s book in The New Republic. Among other things, Posner accused Scalia of resorting to legislative history in spite of Scalia’s avowed abhorrence of doing so. “To say that I use legislative history…is simply, to put it bluntly, a lie,” Scalia retorted at a D.C. forum. “And you can get away with it in The New Republic I suppose, but…not to a legal audience.”

Contact Marcia Coyle at mcoyle@alm.com. Contact Tony Mauro at tmauro@alm.com.