The Supreme Court officially ended its three-month summer recess Monday in kicking off its 235th term, and legal experts are warning that the justices may end up folding to the Trump administration in what one expert predicted would be a series of “once-in-a-century separation-of-powers battles.”

“We’re going to see, among other things, whether the Supreme Court is actually going to say no to Donald Trump on anything,” said Pamela Karlan, the co-director of the Supreme Court Litigation Clinic at Stanford Law School, speaking with The New York Times Monday.

“They’ve tried to dodge and tried to dodge and tried to dodge saying no to him by coming up with procedural ways to say yes to him, but I don’t see how they get out of this term doing it that way.”

The Trump administration has frequently acted beyond what experts consider to be the authority of the executive branch, though its actions have often been supported by the conservative-majority Supreme Court.

Since President Donald Trump took office for his second term, the Supreme Court has sided with Trump in 21 of 23 cases testing his presidential power, 14 of which were decided using what critics have called a “shadow docket,” where rulings are made unsigned, and without reasoning. Examples include the court ruling that Trump held presumptive immunity from criminal prosecution for acts done as president, or the court ruling that lower courts could not institute nationwide injunctions on Trump’s agenda.

Now, after having returned from its summer recess, the Supreme Court is poised to hold what Ivy Gornstein — director of Georgetown Law School’s Supreme Court Institute — predicted would be “one of the most polarizing terms yet.”

Others, like Deepak Gupta, an attorney who frequently argues in cases before the Supreme Court, said that the court’s upcoming term could be a defining moment in American history.

“It’s hard to imagine bigger tests of presidential power than these potentially once-in-a-century separation-of-powers battles,” Gupta said, speaking with The New York Times. “And we’re seeing more than one of them at once.”