Oral arguments at the U.S. Supreme Court can be uncomfortable for the lawyers that argue before the justices. But today it was a justice who was experiencing some discomfort.

Justice Sonia Sotomayor, who entered the courtroom with a noticeable limp, sat through today’s oral arguments with the assistance of a large footrest that was placed under the bench for her. Throughout the morning, the justice would occasionally wince in apparent pain and shift her position in an attempt to get more comfortable.

According to Supreme Court spokeswoman Kathy Arberg, Sotomayor “was experiencing some knee/ligament discomfort.”

As you may recall, Sotomayor was given a similar footrest during her 2009 Senate confirmation hearings after she suffered a broken ankle soon after she was nominated to the Court.

In answering the question of whether state-law design defect claims against vaccine makers are preempted by state law, the justices of the Supreme Court seem to have looked at the relevant statute and asked themselves the question from the “Schoolhouse Rock!” song: Conjunction Junction, what’s your function?

(Press play and sing along as you read the rest of this post, if you like.)

In this morning’s ruling in Bruesewitz v. Wyeth – holding that such claims are preempted – Justice Antonin Scalia’s majority ruling as well as Justice Sonia Sotomayor’s dissenting opinion focused on two conjunctions in the National Childhood Vaccine Injury Act: “if” and “even though.”

The relevant statutory text, §22(b)(1), is:

No vaccine manufacturer shall be liable in a civil action for damages arising from a vaccine-related injury or death associated with the administration of a vaccine after October 1, 1988, if the injury or death resulted from side effects that were unavoidable even though the vaccine was properly prepared and was accompanied by proper directions and warnings. (Emphasis added).

In determining just what kind of side effect is “unavoidable” under the Act, Scalia parsed the meaning of the “even though” clause.

The “even though” clause clarifies the word that precedes it. It delineates the preventative measures that a vaccine manufacturer must have taken for a side-effect to be considered “unavoidable” under the statute. Provided that there was proper manufacture and warning, any remaining side effects, including those resulting from design defects, are deemed to have been unavoidable. State-law design-defect claims are therefore preempted.

If a manufacturer could be held liable for failure to use a different design, the word “unavoidable” would do no work.

Sotomayor, whose dissent was joined by Justice Ruth Bader Ginsburg, had a different view.

Blackletter products liability law generally recognizes three different types of product defects: design defects, manufacturing defects, and labeling defects (e.g., failure to warn). The reference in the “even though” clause to a “properly prepared” vaccine “accompanied by proper directions and warnings” is an obvious reference to two such defects-manufacturing and labeling defects. The plain terms of the “even though” clause thus indicate that §22(b)(1) applies only where neither kind of defect is present.

…The only remaining kind of product defect recognized under traditional products liability law is a design defect. Thus, “side effects that were unavoidable” must refer to side effects caused by a vaccine’s design that were “unavoidable.”

The Court also ruled in CSX Transportation v. Alabama Department of Revenue that a railroad carrier may challenge a non-property tax on the grounds that the tax contains discriminatory exemptions.

Justice Sonia Sotomayor already made history by becoming the Supreme Court’s first Latina justice. But in less than two years on the bench, she has been setting precedent in another way – by speaking frequently and candidly at events across the country, demonstrating her ability to have fun, and developing a following that has made her one if the Court’s most well-known jurists.

In her official capacity, she’s no shrinking violet, notes Bloomberg News’ Greg Stohr. In her written opinions, she has spoken out in opinions and dissents in cases involving issues like prisoners rights and the death penalty. During oral arguments she is vocal as well. In one recent case, she interjected 31 times, Stohr noted.

But she has also made her voice heard off the bench, making appearances at schools, public speaking engagements and law school moot court competitions, often speaking candidly about her own experiences.

“Almost everything I’ve done I’ve been frightened about, including being a Supreme Court justice,” she recently told a crowd at the University of Chicago Law School.

At a recent US Berkeley law moot court competition, she said: “I do moot courts because, every once in a while, I need an injection of hope.”

Though she hasn’t been on the Court long, a Findlaw.com poll found that she is better known than all but two justices: Chief Justice John G. Roberts, Jr. and Justice Clarence Thomas.

And while several other justices also make frequent public appearances at moot court competitions and speaking engagements, Sotomayor’s celebrity justice status has been bolstered by hobnobbing with celebrities like Jennifer Lopez and salsa dancing in public. She can’t even have dinner with a colleague without the press taking note.

Sotomayor seems to be embracing her public persona.

“I think it’s important for the judge to be out in the world,” she said.

In his later years on the bench of the U.S. Supreme Court, Justice John Paul Stevens was not afraid to voice his objection to a certiorari denial in the form of a written dissent or statement accompanying the Court’s orders.

Now, according to USA Today, the Court’s most active cert denial dissenter is Justice Sonia Sotomayor.

So far this term, of the hundreds of appeals requests that have been rejected by the Court – largely without comment – seven have spurred written dissents, and Sotomayor joined in four. Three of them she authored herself, mostly in cases involving Eighth Amendment rights of prisoners.

In one case, Pitre v. Cain, involving a prisoner who claimed he’d been punished with hard labor in 100-degree hear for not taking his HIV medication, Sotomayor dismissed the argument that the prisoner brought the situation on himself.

“[The prisoner] allege[s] not that the respondents denied him medical care but that they punished him for refusing to take medication, or attempted to coerce him to take medication, by subjecting him to hard labor that they knew exceeded his medical limitations,” Sotomayor wrote, adding that she believed the court should have evaluated the claim.

As the justices debated an Arizona law requiring businesses to check the immigration status of their workers Wednesday, Justice Sonia Sotomayor took a different approach from the rest of the justices on one issue: what to call a person who is not authorized to work in the country.

During oral arguments in Chamber of Commerce v. Whiting, most of the justices chose the same words Chief Justice John G. Roberts, Jr. did when he asked: “You don’t disagree that whether or not a company hires illegal workers is related to quality or asserted ability to do business or qualification?”

But Sotomayor used different phrasing. “If the purpose is to regulate undocumented aliens, then it’s struck down,” Sotomayor said.

Sotomayor’s decision to use the word “undocumented” instead of “illegal” seemed to be thoughtful and deliberate. In fact, once during oral argument when she used the word “illegal,” she quickly corrected herself.

“You don’t disagree that Congress at least intended that if someone violated the federal law and hired illegal aliens of Hispanic — undocumented aliens and was found to have violated it, that the state can revoke their license, correct, to do business?” Sotomayor said.

The ABA Journal notes that the term “undocumented” is preferred by the National Association of Hispanic Journalists, because terms like “illegal immigrant” “criminalizes the person rather than the actual act of illegally entering or residing in the United States.”

It is not the first time Sotomayor chose to use the word “undocumented” instead of “illegal.” In fact, it was Sotomayor who introduced the term “undocumented immigrants” for the first time in a Supreme Court opinion last year in Mohawk Industries v. Carpenter.

Summer recess is over for members of Congress, who return to work today in Washington. And President Barack Obama has a message for some members of the Senate: give his judicial nominees and other picks a vote.

“I’ve got people who have been waiting for six months to get confirmed, who nobody has an official objection to and who were voted out of committee unanimously, and I can’t get a vote on them,” Obama said at a White House news conference Friday, according to the BLT Blog.

Obama bemoaned the fact that nominees for federal judgeships and other posts have been stalled by Senate Republicans using procedural speed bumps, if not filibusters.

“We’ve got judges who are pending. We’ve got people who are waiting to help us on critical issues like homeland security,” he said. “And it’s very hard when you’ve got a determined minority in the Senate that insists on a 60-vote filibuster on every single person.”

Meanwhile, Supreme Court Justice Elena Kagan made her social debut as a member of the nation’s highest court. Kagan accompanied Justice Ruth Bader Ginsburg to opening night at the Washington National Opera‘s “Un Ballo in Maschera” Saturday.

In other news:

Sotomayor on the road: During a whirlwind trip where she met with law school students, lawyers, community leaders and the judges before addressing a crowd of 1,300 at the annual dinner of the Legal Aid Society of Cleveland, Justice Sonia Sotomayor said: “It feels like I met all of Cleveland. You rock.” (Cleveland Plain Dealer)

Immigration shift: Although the number of deportations has risen to record levels under the Obama administration, the White House has enacted new policies that will reduce the chances of deportation for millions. (AP’s The Upshot)

Eight-judge bench: The number of cases from which Kagan will recuse herself – based on her involvement as solicitor general and/or other reasons – stands today at 21. (BLT via ABA Journal)

If it seems like Supreme Court confirmation hearings drag on for longer they they should, there is a reason, according to Justice Ruth Bader Ginsburg: the presence of television cameras.

Because the process Senators have for vetting and approving high court nominees is televised, they can’t fight the temptation to play to the cameras, she said.

“The people on the Senate Judiciary Committee have all that free time” to make their case on television, Ginsburg told the audience gathered at the 10^th Circuit Judicial Conference Friday in Colorado Springs, according to the AP.

But Ginsburg stopped short of saying how she felt about allowing cameras in the Supreme Court. Instead, she said, her stance would be guided largely by how comfortable her fellow justices are with the idea.

“When you’re sitting on a collegial bench, if there is any of you who would be extremely discomforted … you would defer to that colleague,” she said.

Ginsburg’s audience included Justice Sonia Sotomayor, who was at the conference to give a private address to judges the next day.

Ginsburg’s late husband Martin Ginsburg had been scheduled to address the conference. The justice delivered remarks her husband prepared before he died of cancer in June.

If it weren’t for her opponents, Justice Sonia Sotomayor may have never become a federal appellate judge – let alone a Supreme Court justice.

Sotomayor, speaking yesterday at Sturm College of Law in Denver, said she was happy as a trial judge when President Bill Clinton tapped her for a post on the 2^nd Circuit. But when opponents resisted at her nomination, it made her want it more.

“If they hadn’t fought so hard, I would have given up earlier,” she said, according to the Denver Post. “I didn’t want to let them beat me.”

When asked if her Puerto Rican ethnicity caused her to face bias, Sotomayor suggested it was the reason some critics questioned her intelligence during her Supreme Court confirmation hearings.

“People kept accusing me of not being smart enough,” Sotomayor said. “Can anyone explain other than I am Hispanic why that would be?”

If you want to chat with Justice Sonia Sotomayor about Chinese food, fine. But don’t ask her about Lindsay Lohan.

That was the lesson for a New York Daily News reporter this week.

Spotted outside Joe’s Shanghai restaurant in New York City’s Chinatown this week, the Supreme Court jurist raved about the food.

“It’s my favorite Chinese restaurant in the city,” Sotomayor said of the eatery, where she dined on soup, dumplings, scallion pancakes, braised bean curd with spinach and other fare with a group of friends. The dumplings were a particular hit, Sotomayor said, because “that’s what they’re famous for.”

But when asked if she would have given Lohan, the troubled actress who was handed a 90-day jail sentence this week, Sotomayor demurred.

“You know I wouldn’t answer that question,” Sotomayor said with a grin. “But I really admire your chutzpah.”

This was a bust news week for the Supreme Court, but it’s also a busy birthday week at the Court.

Two days after Justice Clarence Thomas turned 62, Justice Sonia Sotomayor celebrates her 56^th birthday today.

Happy Birthday Justice!