The U.S. Supreme Court building is seen in Washington, U.S., October 2, 2022. REUTERS/Elizabeth Frantz

By Jan Wolfe and Will Dunham

WASHINGTON (Reuters) -The U.S. Supreme Court is set to scrutinize presidential powers in major cases during its new term opening on Monday, including the legality of President Donald Trump's tariffs and his move to fire officials from the Federal Reserve and another agency set up by Congress with safeguards against political interference.

As is its custom, the court starts its nine-month term on the first Monday of October, with rulings coming by the end of June in the various cases due to be argued. The court, which has a 6-3 conservative majority, has moved American law dramatically rightward under John Roberts, who has now served as U.S. chief justice for two decades.

The court is set to hear disputes involving culture war issues such as race, gay "conversion therapy" and transgender sports participation. Another case concerns election finance restrictions challenged by Trump's Vice President JD Vance.

The justices will hear arguments on November 5 over the legality of Trump's sweeping tariffs after a lower court ruled that the Republican president overstepped his authority in imposing most of these duties under a federal law meant for emergencies. The case tests one of Trump's boldest assertions of executive power. The arguments involve challenges to the tariffs by 12 U.S. states and various businesses.

The economic stakes are massive, Bradley University professor Taraleigh Davis said.

"If Trump loses, existing tariffs could be invalidated immediately, disrupting markets and trade negotiations," Davis added. "If he wins, it confirms presidents can unilaterally reshape the economy through tariffs without congressional approval."

The court in January will hear arguments concerning Trump's attempt to remove Federal Reserve Governor Lisa Cook in a major legal battle over the first-ever bid by a president to fire a Fed official as he challenges the central bank's independence.

In creating the Fed in 1913, Congress passed a law that included provisions to shield the central bank from political interference, requiring governors to be removed by a president only "for cause," though it does not define the term nor establish procedures for removal. The law was never previously tested in court.

A judge has ruled that Trump's claims that Cook committed mortgage fraud before taking office, which Cook denies, likely were not sufficient grounds for removal under this law. Cook, the first Black woman to serve as a Fed governor, has called Trump's claims against her a pretext to fire her for her monetary policy stance.

The justices, in scheduling the arguments, did not act on the Justice Department's request to let Trump remove Cook while the case plays out, thus leaving her in the job for now.

ANOTHER FIRING

The justices in December will hear arguments concerning Trump's firing of Rebecca Slaughter, a Democratic member of the Federal Trade Commission. The case gives the conservative justices a chance to overrule the court's 1935 precedent that upheld job protections enacted by Congress to insulate leaders of certain federal agencies from presidential control.

The court allowed Trump's removal of Slaughter while her legal challenge plays out.

More major cases involving presidential powers could be coming. Trump's administration already has asked the justices to decide the legality of his bid to limit birthright citizenship.

Since issuing the final rulings of their last term in June, the justices have remained busy handling the administration's emergency requests to let various Trump actions impeded by lower courts take effect while litigation continues. The court has backed Trump in almost all of these cases.

GAY 'CONVERSION THERAPY'

The first major case to be argued during the new term comes on Tuesday in a Christian professional counselor's challenge on free speech grounds to a Democratic-backed Colorado law banning "conversion therapy" intended to change a minor's sexual orientation or gender identity. A lower court rejected the plaintiff's claim that the law censors her communications with clients in violation of the U.S. Constitution's First Amendment protections against government abridgment of free speech.

The court later will hear bids by Idaho and West Virginia to enforce Republican-backed state laws banning transgender athletes from female sports teams at public schools.

On October 15, it hears arguments over a Louisiana electoral map that raised the number of Black-majority U.S. congressional districts in the state. The case gives the conservative majority a chance to gut a key provision of the Voting Rights Act, the landmark 1965 law intended to prevent racial discrimination in voting.

The Vance case involves a federal campaign finance law provision limiting spending by political parties in coordination with candidates seeking office. Vance and other Republicans challenged it as a First Amendment violation. Lower courts disagreed.

"It's certainly going to be a term that not only is legally important, which every term is, but also politically important and culturally salient," University of Virginia law professor Xiao Wang said.

(Reporting by Jan Wolfe and Will Dunham, Editing by Rosalba O'Brien)