WASHINGTON — The Supreme Court returns to the bench on Monday to confront not only a docket studded with momentous issues but also a new dynamic among the justices.


The coming term will probably include major decisions on affirmative action in higher education admissions, same-sex marriage and a challenge to the heart of the Voting Rights Act of 1965. Those rulings could easily rival the last term’s as the most consequential in recent memory.


The theme this term is the nature of equality, and it will play out over issues that have bedeviled the nation for decades. “Last term will be remembered for one case,” said Kannon K. Shanmugam, a lawyer with Williams & Connolly. “This term will be remembered for several.”


The term will also provide signals about the repercussions of Chief Justice John G. Roberts Jr.’s surprise decision in June to join the court’s four more liberal members and supply the decisive fifth vote in the landmark decision to uphold President Obama’s health care law. Every decision of the new term will be scrutinized for signs of whether Chief Justice Roberts, who had been a reliable member of the court’s conservative wing, has moved toward the ideological center of the court.


“The salient question is: Is it a little bit, or is it a lot?” said Paul D. Clement, a lawyer for the 26 states on the losing side of the core of the health care decision.


The term could clarify whether the health care ruling will come to be seen as the case that helped Chief Justice Roberts protect the authority of his court against charges of partisanship while accruing a mountain of political capital in the process. He and his fellow conservative justices might then run the table on the causes that engage him more than the limits of federal power ever have: cutting back on racial preferences, on campaign finance restrictions and on procedural protections for people accused of crimes.


It is also possible that the chief justice will become yet another disappointment to conservatives, who are used to them from the Supreme Court, and that he will join Justice Anthony M. Kennedy as a swing vote at the court’s center. There is already some early evidence of this trend: in each of the last three terms, only Chief Justice Roberts and Justice Kennedy were in the majority more than 90 percent of the time.


“We all start with the conventional wisdom that Justice Kennedy is going to decide the close cases,” said Mr. Clement, who served as United States solicitor general under President George W. Bush. “We’ve all been reminded that that’s not always the case.”


The texture of the new term will be different, as the court’s attention shifts from federalism and the economy to questions involving race and sexual orientation. The new issues before the court are concrete and consequential: Who gets to go to college? To get married? To vote?


On Oct. 10, the court will hear Fisher v. University of Texas, No. 11-345, a major challenge to affirmative action in higher education. The case was brought by Abigail Fisher, a white woman who says she was denied admission to the University of Texas based on her race. The university selects part of its class by taking race into account, as one factor among many, in an effort to ensure educational diversity.


Just nine years ago, the Supreme Court endorsed that approach in a 5-to-4 vote. The majority opinion in the case, Grutter v. Bollinger, was written by Justice Sandra Day O’Connor, who said she expected it to last for a quarter of a century.


But Justice O’Connor retired in 2006. She was succeeded by Justice Samuel A. Alito Jr., who was appointed by Mr. Bush and who has consistently voted to limit race-conscious decision making by the government. Chief Justice Roberts, another Bush appointee, has made no secret of his distaste for what he has called “a sordid business, this divvying us up by race.”


Justices Kennedy, Antonin Scalia and Clarence Thomas all dissented in the Grutter case, and simple math suggests that there may now be five votes to limit or overturn it.


The reach of such a decision could be limited by the idiosyncrasies of the admissions system in Texas. The university provides automatic admission to students in Texas who graduate in roughly the top 10 percent of their high school classes. That approach generates substantial diversity, partly because many Texas high schools remain racially homogeneous.


Ms. Fisher narrowly missed the cutoff at a high school whose students have above-average test scores for the state. She was rejected for one of the remaining spots under the part of the admissions program that considers applicants’ race.


The court may uphold the Texas system under Grutter, or it may rule against it on narrow grounds by saying, for instance, that race-conscious admissions are forbidden where a race-neutral method — like the 10 percent program — can be said to be working.


But the court may also follow the health care ruling with a second landmark decision, this one barring racial preferences in admissions decisions altogether. Given persistent achievement gaps, even after controlling for family income, such a ruling would make the student bodies of many colleges less black and Hispanic and more white and Asian.


The court will probably also take on same-sex marriage. “I think it’s most likely that we will have that issue before the court toward the end of the current term,” Justice Ruth Bader Ginsburg said at the University of Colorado on Sept. 19.