WASHINGTON (Reuters) - The Trump administration’s ability to win over the U.S. Supreme Court will be put to the test when the nine justices begin their new term on Monday with major cases awaiting on voting rights, religious liberty, union funding and class-action suits.

FILE PHOTO: The building of the U.S. Supreme Court in Washington, U.S., June 26, 2017. REUTERS/Yuri Gripas/File Photo

President Donald Trump’s Justice Department already has flipped the government’s position in some important cases, reversing the stance taken under Democratic former President Barack Obama, and could have a receptive audience on the court, whose term runs through June.

The addition of Trump’s appointee Neil Gorsuch in April restored the court’s 5-4 conservative majority, as the new justice prepares to begin his first full term.

The administration has backed companies against employees and supported voting laws that critics say could prevent eligible people from casting ballots. [Graphic showing major cases: tmsnrt.rs/2y3eCs6]

It also has reversed the Obama administration’s stance in support of protections for gay workers under federal law, an issue that could reach the court within weeks.

The Supreme Court generally gives special deference to the views of the U.S. solicitor general, the federal government’s top lawyer. Trump’s appointee Noel Francisco holds the job. But some justices may look dimly upon the government abruptly changing its position in cases.

Former Justice Department lawyer Pratik Shah said a flip-flop can provide an opening for justices sympathetic to the view of the prior administration, who can ask: “What in the law has changed to warrant a different view?”

The court’s oldest justice, 84-year-old liberal Ruth Bader Ginsburg, has called the upcoming term “momentous” owing to the importance of the cases on the docket.

On Tuesday, the term’s second day, the justices are due to hear a case that could help shape U.S. elections for decades involving the long-standing practice of a majority party manipulating electoral boundaries for future elections to try to cement their hold on power.

Wisconsin is appealing a lower-court ruling that the way the Republican-led legislature redrew boundaries following the 2010 census was so far-reaching in its bid to marginalize Democratic voters that it violated the Constitution.

In a case expected to be argued in December involving free speech, religious liberty and gay rights, the justices will weigh whether a Denver-area baker who cited his Christian beliefs in refusing to make a wedding cake for a gay couple can be penalized for violating a Colorado anti-discrimination law.

The new administration has backed the baker, infuriating groups that support gay, lesbian, transgender and bisexual rights.

“President Trump said on the campaign trail that he’s an advocate for LGBT people, but actions speak much louder than words,” said James Esseks, an American Civil Liberties Union lawyer who works on gay rights issues.

The Supreme Court on Monday canceled arguments that had been scheduled for Oct. 10 in what would have been the biggest case of the term, whether Trump’s ban on people entering the United States from several Muslim-majority countries amounted to unconstitutional discrimination against Muslims. The action came after a temporary ban expired and the administration announced a new set of restrictions.

‘ONE-TWO PUNCH’

A case on the first day of the term on Monday presents a rarity, with the administration facing off against one of the federal government’s own agencies, the National Labor Relations Board.

“That will be a first for me in the nearly 25 years I have served on the court,” Ginsburg said at a Georgetown Law Center event on Sept. 20.

The administration is no longer defending the NLRB’s position that employment agreements in which businesses require workers to waive their rights to bring class-action claims are invalid. The waivers compel workers to individually arbitrate disputes with employers rather than bringing collective lawsuits with co-workers.

The court’s conservative majority is expected to be sympathetic to the arguments made by employers.

The court on Thursday agreed to hear a case that could end an important source of funding for unions representing police, teachers and other government employees.

The dispute centers on fees that some states require non-union members to pay to unions in lieu of dues to fund collective bargaining and other organized labor activities.

Claire Prestel, associate general counsel of the Service Employees International Union (SEIU), said those cases could lead to a “one-two punch against workers.”

The Obama administration backed the unions in a similar case in which the justices ended with a 4-4 deadlock last year. The Trump administration may change course and back the anti-union challengers.

In another about-face, Trump’s Justice Department has also sided with Ohio in its bid to revive a state policy of purging infrequent voters from voter-registration lists, reversing the Obama administration’s stance that the practice was illegal.

Obama’s former attorney general, Eric Holder, joined a friend-of-the-court brief criticizing the reversal, saying the Trump administration policy departed from the government’s interpretation of Ohio’s law dating back more than 20 years and spanning administrations from both parties. The justices are set to hear that case on Nov. 8.