WASHINGTON — One momentous case down, another equally historic decision to go.

The Supreme Court returns to the bench today with 17 cases still unresolved, including its first-ever comprehensive look at the Second Amendment’s right to bear arms.

The guns case — including Washington, D.C.’s ban on handguns — is widely expected to be a victory for supporters of gun rights. Top officials of a national gun control organization said this week that they expect the handgun ban to be struck down, but they are hopeful other gun regulations will survive.

Last week, the court delivered the biggest opinion of the term to date with its ruling, sharply contested by the dissenting justices, that guarantees some constitutional rights to foreign terrorism detainees at Guantanamo Bay, Cuba. The 5-4 decision, which Justice Anthony Kennedy wrote for his four more liberal colleagues, was the first case this term that broke along ideological lines.

The conservative-liberal split was seen frequently last term, including in cases that limited abortion rights, reined in voluntary school desegregation plans, made it harder to sue for pay discrimination, and prodded the Bush administration to combat global warming by regulating tailpipe emissions. Justice Kennedy was the only justice in the majority in all those cases, siding with conservatives in all but the global-warming dispute.

It’s hardly unusual that the cases that take until late spring to resolve are the most contentious and most likely to produce narrow majorities.

The dispute over gun rights poses several important questions. Although the Second Amendment was ratified in 1791, the court has never definitively said what it means to have a right to keep and bear arms. The justices also could indicate whether, even with a strong statement in support of gun rights, Washington’s handgun ban and other gun control laws can be upheld.

Officials at the Brady Campaign to Prevent Gun Violence said recently that they expect Washington’s 32-year-old handgun ban to fall but believe that background checks, limits on large-volume gun sales, and prohibitions on certain categories of weapons can survive.

In addition to the guns case, the justices are still weighing whether Exxon Mobil Corp. has to pay a $2.5 billion punitive damages judgment over the Exxon Valdez disaster in Alaska in 1989 and whether people convicted of raping children may be executed.