How the court system adapts between two very different presidential administrations

Backing employers over employees. Backing the state of Ohio over groups involved in voter registration. Backing a narrow reading of a sexual discrimination law over a broad one.

Those are just some of the legal about-faces President Trump's administration is making at the Supreme Court and in lower courts.

The Trump administration has found itself in court defending a variety of new policies: the president's travel ban, the phasing out of a program protecting young immigrants, and the revisiting of a policy that had allowed transgender individuals to serve openly in the military. But it's also dealing with lawsuits that were in progress before the president took office – and asserting positions different from those of the Obama administration.

The Office of the Solicitor General, the Justice Department office that represents the federal government at the Supreme Court and determines what position it will take in federal appeals court cases, does some position switching every time the White House changes parties. But the office prizes its reputation as largely nonpartisan and switches positions with "a great deal of trepidation," said Gregory Garre, who served as solicitor general under former President George W. Bush.

"The office's currency and credibility before the court depends on it not being viewed as a political institution," Mr. Garre said. He said Supreme Court justices, and Chief Justice John Roberts in particular, have given the office a hard time in court about flipping positions.

On Monday, the first day of its new term, the Supreme Court will hear its first case in which the Trump administration is reversing course from its predecessor. In one of the most important business cases of the term, the Obama administration had backed employees in a dispute with their employers over arbitration agreements. Now, the Trump administration is backing employers.

A federal agency, the National Labor Relations Board, is being permitted to defend the original position, meaning that two government lawyers will argue against each other. Justice Ruth Bader Ginsburg has said that the unusual lineup "will be a first for me in the nearly 25 years I've served on the court."

The justices will soon consider a case in which the government now supports a method Ohio uses to remove people from voter rolls. When the case was being heard in a federal appeals court, the Obama administration argued that the method, which puts someone on the path to being removed from the rolls if they haven't voted for two years, violates federal law.

Samuel Bagenstos, a University of Michigan law professor and former Justice Department official, called the switch in a longstanding position "stunning" because it reversed a view held for more than 20 years by Republican and Democratic administrations alike.

While the highest-profile shifts in position may be those at the Supreme Court, the administration has also altered course in cases at lower-level courts. In cases about pollution-control rules put in place by the Obama administration, the Trump administration has asked for pauses in the litigation so the rules can be re-evaluated, said Pat Gallagher, the director of the Sierra Club's environmental law program.

In a case out of Texas, the Obama administration had joined groups suing over a controversial voter ID law. The Trump administration, in contrast, has abandoned the argument that the state passed ID rules with discrimination in mind. It said changes signed by Texas' governor should satisfy the courts.

The Trump administration has also aggressively shifted positions in cases involving gay rights, said Human Rights Campaign legal director Sarah Warbelow. In a New York case involving a skydiving instructor who alleged he was fired after telling a customer he was gay, the Trump administration's Justice Department weighed in to argue that a federal law barring "sex" discrimination means discrimination based on gender and doesn't cover sexual orientation. The Equal Employment Opportunity Commission under former President Barack Obama took the opposite view.

The Trump administration is also supporting a Colorado baker who refused to make a wedding cake for a gay couple because of his religious beliefs, a case now before the Supreme Court.

Donald Verrilli, who served as solicitor general from 2011 to 2016, said the Obama administration either wouldn't have weighed in on the case at all or would have supported the couple. But Mr. Verrilli, who himself backed position switches when he was solicitor general, declined to discuss other about-faces by his former office.

"It's a hard job. You know, you've got to make difficult judgments in that job," Verrilli said. "I'm sure they're doing their best."

This story was reported by The Associated Press.