Justice Ruth Bader Ginsburg wanted to make one thing crystal-clear over the summer: She has no immediate plans to step down. She is taking her spot on the bench to begin the new term today.

She spent the summer traveling, giving speeches and reiterating in several print interviews that she expects to stay on the Supreme Court. For now. "My answer is, as long as I can do the job full steam, I will," Ginsburg told the AP's Mark Sherman.

She celebrated her 80 th birthday last March and has spent 20 years on the Supreme Court bench.

So what keeps her going?

"This fantastic job," Ginsburg told NPR's Michel Martin at a Georgetown Law event celebrating women's rights a few weeks ago.

"My only weapon is the power to persuade, so I work terribly hard on my opinions," Ginsburg said.

Some legal experts believe she is just entering her prime.

"It seems in the last two years you are on fire," Jeffrey Rosen, the President of the National Constitution Center, told the Justice in early September.

She is perhaps best known for her 1996 landmark majority opinion striking down the all-male admissions policy at the state-funded Virginia Military Institute. She has, in the past, been on the other side, dissenting with force in cases regarding such issues as pay discrimination and abortion restrictions.

But in the last few years she has taken on a new role on the Court. In 2010 Justice John Paul Stevens retired at 91 years old. Ginsburg became the senior member of the Court's four member liberal wing. In those controversial cases when the Court splits 5-4 on ideological lines, she gets to choose who will write the dissent.

Rosen asked Ginsburg what emboldened her to express herself so powerfully in recent cases including those on health care, affirmative action and the Voting Rights Act.

"I had a good model," she replied, referring to Stevens.

She said that while she was writing an opinion on one section of the health care case, she held a strategy session with three of her liberal colleagues, "so I could make sure I was speaking for the four of us, and not just myself."

In the partial dissent Ginsburg rejected the Court's contention that the individual mandate was not a valid exercise of Congress's power under the Commerce Clause.

She did not mince her words: "The Chief Justice's crabbed reading of the Commerce Clause harks back to the era in which the Court routinely thwarted Congress' efforts to regulate the national economy in the interest of whose who labor to sustain it."

She attacked what she called the "broccoli horrible" concern that if the government could mandate a minimum coverage provision it could also mandate the purchase of green vegetables.

"Consider the chain of inferences the Court would have to accept to conclude that a vegetable-purchase mandate was likely to have a substantial effect on the health-care costs borne by lithe Americans," Ginsburg wrote. The individuals would actually have to eat the vegetables, she argued, and cook them in a healthy way (steamed! Not fried!) .

She said accepting the "broccoli horrible" as a reason to deny Congress the power to pass the individual mandate was "specious" logic.

"Justice Ginsburg has always been a great justice, but in the past two years she's found her voice as the leader of all of the liberal justices on the Court," Rosen said after his talk with Ginsburg.

Last spring a majority of the Court struck down a key provision of the Voting Rights Act and essentially blocked Section 5 of the law, which required certain states with a history of racial discrimination to get federal approval before changing election laws. Ginsburg unleashed her fury in a dissent joined by her liberal colleagues.

"The sad irony of today's decision lies in its utter failure to grasp why the VRA has proven effective," Ginsburg wrote. She compared racial discrimination to a "vile infection" and said early attempts to protect against it was like "battling the hydra."

She said throwing out a section of the law "when it has worked and is continuing to work to stop discriminatory changes is like throwing away your umbrella in a rainstorm because you are not getting wet."

In Fisher v. University of Texas, an affirmative action case, Ginsburg was the sole dissenter. The case concerned the admissions plan at the University of Texas that takes race into consideration on a limited basis. The justices deliberated over the case for eight months and finally, to the relief of supporters of affirmative action, issued a narrow opinion that did not disturb precedent and sent the case back to the appeals court for another look.

Justice Elena Kagan was recused from the case, presumably because she dealt with it in her previous job as solicitor general. Justice Stephen Breyer and Justice Sonia Sotomayor joined the majority opinion. Not Ginsburg.

Instead, her dissent contained strong support for the university's plan.

"I would not return this case for a second look," she wrote.

Last term the Court also considered two major gay rights cases. Ginsburg joined Justice Anthony Kennedy's majority striking down a section of federal law that defined marriage as between a man and a woman. The law denied federal benefits to those same-sex couples who were legally married in their states. In the second case, Ginsburg joined Chief Justice John Roberts' opinion dismissing on procedural grounds a case concerning California's 2008 ban on gay marriage. The opinion was a victory for supporters of gay rights activists as it cleared the way for same-sex marriage to resume in the state.

The Court did not rule on whether there is a constitutional right to gay marriage under the Constitution.

After the decisions were issued, Ginsburg agreed, for the first time, to officiate at a same-sex marriage ceremony. She performed the marriage of her longtime friend Michael M. Kaiser, president of the Kennedy Center, and his now husband, John Roberts (an economist - and no relation to Ginsburg's bench mate!).

"No one should be alarmed to learn that Justice Ginsburg has personal policy preferences relating to same sex marriage, " says Carrie Severino of the conservative Judicial Crisis Network. "The key question is whether she can set aside those personal policy preferences to decide cases fairly and impartially, on the basis of the Constitution. I think we all know the answer to that question, and it is that Justice Ginsburg has a personal bias in favor of gay marriage so she will always vote to create a coast-to-coast right to gay marriage, regardless of what the law and the constitution call for."

In almost every interview Ginsburg is asked whether she may soon retire given her age and her two previous bouts with cancer.

Howard J. Bashman, a lawyer who publishes the popular How Appealing Blog, wrote recently that Ginsburg may want a president with similar views to her own to nominate her successor.

"The most certain way to ensure such a replacement is for Justice Ginsburg to retire during the Obama presidency, and the most certain way to obtain confirmation of such a replacement is for the confirmation process to occur during the current Senate, rather than with a Senate of unknown composition that will exist in 2015-2016 (and the run-up to another presidential election)."

Ginsburg has repeated that she has no plans to step down in the immediate future.

When the question came up at the National Constitution Center event, Ginsburg simply responded, "Think about what is coming up next term." And then launched into the cases at hand.