Update at 10:30 a.m. ET. Today's Major Ruling; Key Part Of 1965 Voting Rights Act Is Ruled Unconstitutional:

"By a 5-to-4 decision, the Supreme Court has struck down a key provision of the 1965 Voting Rights Act that establishes a formula to identify states that may require extra scrutiny by Justice Department," Eyder writes .

The decision in Shelby County v. Holder is posted here . It's the only one of the most-anticipated cases in which rulings were issued Tuesday. According to Chief Justice John Roberts, the court will finish its work for the term on Wednesday. So, that's when we'll hear about its decisions on two high-profile cases involving gay rights.

Update at 10:12 a.m. ET. Key Section Of Voting Rights Act Ruled Unconstitutional:

The Supreme Court's first major decision of the day has been released: By a 5-4 vote the justices have ruled that Section 4 of the Voting Rights Act is unconstitutional. We'll have more on the ruling as the morning continues. And follow SCOTUSblog's updates in the box below.

Our original post:

Will it be voting rights? Same-sex marriage? Both? Neither?

The justices of the Supreme Court are due to take their seats again at 10 a.m. ET Tuesday to release what could be their last decisions before taking off for the summer.

Monday, as we reported , they knocked one high-profile case off their list. The justices told the U.S. Court of Appeals for the Fifth Circuit to take another look at a challenge raised to the University of Texas' affirmative action efforts.

Now, although we said this could be the justices' last "decision day" for this term, it's also very possible they'll be back in a day or so to issue some additional rulings on cases that still haven't closed.

What are the big cases yet to be decided?

— Shelby County v. Holder, in which the issue is whether times have changed and the 1965 Voting Rights Act should no longer apply to that Alabama county.

— Hollingsworth v. Perry and United States v. Windsor , two potentially landmark cases on gay marriage.

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