With the US political class still reeling from the climax of last season’s finale, the supreme court returns on Monday for a new series of cases, and all indications point to equally dramatic plot twists involving race, class and murder.

While 2014-15 will be remembered for surprise wins by the liberal wing of the court, particularly two blockbuster decisions endorsing gay marriage and Obamacare , legal experts anticipate this year will see a clutch of decisions that reassert the power of the conservative majority.

This period leading up to the forthcoming US election in November 2016 will be closely watched in any event, since the next president is likely to shape the future direction of the court for a generation by replacing up to four of the ageing justices during his or her time in the White House.

Chief justice John Roberts, who was appointed by President George W Bush in 2005, has already been criticised by Republican presidential hopefuls for failing to live up to conservative expectations. Some analysis even suggests he has presided over the greatest percentage of liberal decisions by the nine justices since 1969.

But, if pundits are correct in their interpretation of the 34 cases already on the docket this coming season, then the court’s conservative majority may soon prove itself better at playing the long game than its critics on the right acknowledge.

“The big question about the Roberts court has always been is it radically Conservative, with a big C, or moderately conservative, with a small C,” says David Cole, a law professor at Georgetown University.

“If the court comes out with more radical decisions this term, it’s because they have taken on cases in areas where they have been pretty darned conservative, like race and affirmative action,” he told the Guardian.

Union dues

Perhaps the strongest example of the right’s careful choice of targets this year is the return of a lawsuit seeking to clip the wings of American labor unions by removing their ability to collect dues from employees, where workplaces have voted in favour of collective bargaining.

The principle that unions have a right to charge all employees a fee to represent them, even those who choose to waive the political component of their membership, was first established by the court back in 1977 in a landmark case known as Abood versus Detroit Board of Education .

But in a new case against the California Teachers Association, brought by Orange County teacher Rebecca Friedrichs and others, the supreme court is being asked to overturn Abood on the grounds that forcing union members to pay union dues for collective bargaining infringes on those members’ first amendment right to free speech, because it forces them to pay to take part in a political act they do not agree with.

“Why is the court reconsidering this issue? I think it’s a matter of a change in the court and a change in the political climate toward unions,” claims Ann Hodges, professor of law at the University of Richmond, during a panel discussion with Cole and others at the American Constitution Society.

Though the case only directly challenges California’s so-called Fair Share law for public sector employees, it follows two similar decisions by the Roberts court in 2012 and 2014 that suggest there is appetite on the bench to overturn the current system nationwide.

“In both those cases [conservative-leaning justice Samuel] Alito heavily criticised Abood and essentially issued an invitation to challenge ‘fair share fees’ and seek to overturn Abood,” says Hodges. “The plaintiffs here [in Friedrichs v California Teachers Association] took up that invitation.”

This analysis is shared by experts of varying political persuasions.

“It seems to me as if this is one where the writing is on the wall,” agrees Kannon Shanmugam, a top supreme court lawyer originally from Kansas who once clerked for conservative hero, Justice Antonin Scalia.

“If I had to guess I would say the court essentially invited a test case,” he adds. “And I tend to think the court already has a pretty good idea of what it is going to do on this issue.”

Affirmative action at universities

Similar pessimism on the left and optimism from the right surrounds another big case facing the court this year relating to affirmative action policies used by university admissions departments.

Fisher v University of Texas, as this case is known, sees the return to the court of another well-drilled setpiece of the American culture wars – this time even with the same plaintiff, Abigail Fisher, whose first attempt to sue the university in Austin for favouring black and Latino students was knocked back by the court two years ago.

The case relates narrowly to UT’s ability to choose a small subset of its students with limited reference to their racial backgrounds – a system designed to avoid a ban on outright quotas.

But in another example of the gradual chiseling away of already-fragile legal precedent , some suspect the case is returning to court primarily because of its ability to have an impact on two more substantial affirmative action cases pending against Harvard University and the University of North Carolina.

“It’s not clear why the court has taken this case, and I’m afraid that it is to impact the Harvard case and the University of North Carolina case,” says Deborah Archer, professor at New York Law School and a former assistant counsel at the NAACP Legal Defense Fund. “I think this court plays the long game and sets up the stage – just as they did with voting rights.”

Voting rights

The succession of related cases she refers to culminated in the repeal of part of the Voting Rights Act in 2013. The 1965 act had forced many southern states to seek permission from federal authorities in Washington to make any changes to their electoral rules, such as introducing literacy tests that might reduce voter registration among minority groups.

But the reversal of this landmark protection from the civil rights era is not the end of the threat as far as the NAACP and other campaign groups are concerned.

Related: 'This is our Selma': North Carolina voting rights trial threatens 50 years of progress

This year the supreme court will hear another voters’ rights case from Texas called Evenwel v Abbott which, on the face of it, seeks to decide the relatively neutral question of whether states should consider population size or the number of eligible voters when deciding how to set electoral boundaries of even size.

Some argue this is one for legal geeks alone and see it as unconnected to the other cases.

“Supreme court precedents do not set a lot of light on this issue,” says Shanmugam, who works for Williams & Connolly law firm in Washington. “It’s hard to calculate the impact but I have heard it suggested that the challenger’s position would help Republicans.”

But other legal experts are adamant that there is a racial aspect to the case.

“If you use the criteria that the plaintiffs are advancing you end up with whiter districts, richer districts,” says Archer, the ex-NAACP lawyer. “We have to look at this against the backdrop of increasing number of voter ID laws that are cropping up around the country.”

Some simply point to the common involvement of a controversial former stockbroker named Edward Blum in paying for both the challenges to affirmative action and this redistricting case as an indication of the motives behind it.

“I don’t know the mathematics of how it would work out but I do know one thing,” says Alan Morrison of George Washington University law school. “Edward Blum is financing this case and he also financed Fisher and that probably tells you something about what he thinks the outcome is going to be.”

Class action

Conservative interest groups are also heavily involved in three cases due this year that seek to limit the ability of consumers and employees to bring class action suits against companies.

The most prominent of these is a challenge brought by Tyson Foods against a $5.8m judgment awarded against the company for skipping overtime pay at an Iowa meat-processing plant

For business lobbyists such as the US Chamber of Commerce the case is a good chance to curb what they see as an epidemic of costly class action case.

Liberal lawyers (many of whom profit from fees made in these often speculative cases) argue the court risks limiting access to justice for ordinary people if it sides with corporate interests.

Capital punishment

Another group of cases more eagerly awaited by liberals relates to capital punishment, where there has been a gradual drift away from state executions in recent years.

Already the number of state executions has fallen from 98 in 1999 to just 35 in 2014 and 20 so far this year.

Juries, in particular, are much more reluctant to recommend the death penalty – leading to around 80 death sentences a year compared with more than 300 a year in the 1990s.

Now, three linked cases – Kansas v Gleason , Kansas v Carr and Hurst v Florida – will examine whether juries should be given even more encouragement to err on the side of caution and avoid potentially fatal miscarriages of justice.

“It may well be the court keeps the death penalty but it will be prepared to adopt minor clarifications of the rules that reduce the risk that we send the wrong people to death,” predicts Georgetown’s professor Cole.

These death penalty cases will also be the first of the big themes heard next in this supreme court session, with oral arguments slated for October 7 and 13.

Several liberal justices led by Stephen Bryer and Ruth Bader Ginsburg would even like to see the court take on the question of the constitutionality of the death penalty itself, arguing that the dwindling number of executions makes its imposition an increasingly arbitrary exercise of justice that could breach the constitution’s prohibition against “cruel and unusual punishments”.

But such a ruling may need to wait for the far larger decision facing American voters in November 2016 when they pick a president who is likely to face an unprecedented wave of justices reaching the age when they have traditionally retired, or died.

“Given how old they are, it’s not that unlikely actuarially, that the next president will makes those appointments – especially if they serve two terms, when it becomes virtually certain,” says Cole. “So this is a critical time for the future of the constitution.”

Most court-watchers agree that a Republican president would have the most dramatic impact.

“If a Republican gets to replace Ginsburg or Breyer, the two oldest Democrats, that changes the court to five solidly conservative justices, and renders Kennedy irrelevant in most instances,” Cole adds, referring to Anthony Kennedy, considered a sometimes unreliable conservative. “Equally, if a Democrat gets elected and gets to replace Scalia or Kennedy, the two oldest on the Republican side, that also dramatically changes the court.”

Were either to happen, it may make the see-saw of the last two court sessions pale into insignificance.

“Every [presidential] election people say this is about the future of the Supreme Court and the constitution, this time it’s true,” concludes Cole.

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