This morning saw significant activity at the U.S. Supreme Court. Although we did not get a ruling in the health care reform case (aka Obamacare), SCOTUS did hand down a number of important opinions. Check back later today, when we expect to have color commentary from our Supreme Court correspondent, Matt Kaiser, who attended the proceedings in person.

In the meantime, here’s a quick and dirty summary of what transpired at One First Street this morning, including links to the underlying opinions. The most high-profile case was the Court’s decision on the controversial Arizona immigration law, but there were other major cases that were resolved today as well….

First things first: a very happy birthday to Justice Sonia Sotomayor! The Wise Latina is now one year older and wiser — but still a spring chicken by SCOTUS standards, at 58 years old.

Now, on to the opinions. The first decision handed down was a per curiam reversal of the Montana Supreme Court in American Tradition Partnership, Inc. v. Bullock (opinions here), a closely watched campaign-finance case implicating Citizens United. In a curt, one-page per curiam, the Court summarily reversed — ouch. Can you say “benchslap”?

Four justices — you can probably guess which ones — dissented. In the brief dissenting opinion, just a shade over one page, Justice Breyer reiterated his disagreement with the Citizens United decision, then went on to explain: “I would vote to grant the petition for certiorari in order to reconsider Citizens United or, at least, its application in this case. But given the Court’s per curiam disposition, I do not see a significant possibility of reconsideration. Consequently, I vote instead to deny the petition.”

Second, the Court handed down Miller v. Alabama (opinions here). In an opinion by Justice Kagan, SCOTUS held “that mandatory life without parole for those under the age of 18 at the time of their crimes violates the Eighth Amendment’s prohibition on ‘cruel and unusual punishments.'” The Court’s four more “liberal” members were joined by Justice Kennedy, who has generally tilted leftward on sentencing matters (think “evolving standards of decency” and all that). All four conservative justices filed separate dissents, and Justice Alito read his dissent from the bench.

Third, the Court handed down its decision in Arizona v. United States (opinions here). Justice Kennedy wrote for the Court, reversing the Ninth Circuit in part and affirming in part — i.e., upholding some parts of the law and finding others preempted by federal law. Many of the key provisions of the Arizona law were held to be preempted by federal law, in what Tom Goldstein of SCOTUSblog called “a significant win for the Obama Administration,” but the Court did allow to stand the “check your papers” provision that commands officers to check the immigration status of drivers they’ve detained. (Note that this ruling applies only to the preemption challenges raised to the Arizona law in this specific case; it does not resolve any constitutional challenges — e.g., claims that the law involves unconstitutional racial profiling.)

Justices Scalia, Thomas, and Alito concurred in part and dissented in part. Justice Scalia read from his dissent, noting at the outset that he would have upheld the Arizona law in its entirety. Amy Howe of SCOTUSblog had this interesting observation: “As part of Scalia’s statement in dissent, he is commenting on the president’s announcement about suspending deportation of illegal immigrants who came to the U.S. as children — something that was not part of the case.”

Finally, the Court issued some certiorari grants and announced its schedule for the rest of the week. It looks like the last day of October Term 2011 will be this Thursday, June 28 — aka D-Day for O-Care. It also seems, according to knowledgeable Court watcher Tom Goldstein, that Chief Justice Roberts will be writing for the Court in the health care case (perhaps in part with Justice Kennedy).

So far there have been no leaks out of the Court in the high-profile case. Can the silence hold for a few more days? Probably — but we shall see….

P.S. Check back later today for detailed analysis from Matt Kaiser. And thanks to our friends at SCOTUSblog for keeping us so well-informed about the Court on a real-time basis. If you’d like to take a behind-the-scenes look at SCOTUSblog, check out this piece by Dan Diamond for Forbes (mentioned previously in Morning Docket).

Miller v. Alabama [Supreme Court of the United States]

Arizona v. United States [Supreme Court of the United States]

American Tradition Partnership, Inc. v. Bullock [Supreme Court of the United States]

Live blog of orders and opinions [SCOTUSblog]