A Supreme Court ruling limiting the ability of judges to block White House policies will bring a wave of urgency and uncertainty to the federal courts, experts said, as plaintiffs pursue new ways of blocking President Trump’s agenda and judges sort out how to apply the court’s complex ruling.

On Friday, the Supreme Court ruled that district court judges likely exceeded their authority with so-called nationwide injunctions.

Also known as universal injunctions, they have been used by judges more than two dozen times to block pieces of Mr. Trump’s second-term agenda, including freezes on federal funding, changes to voting rules and limitations on birthright citizenship — all with the stroke of a pen.

Now, the justices ruled, the lower courts can only block government policies for “each plaintiff with standing to sue.”

Those plaintiffs can still win rulings that affect a large number of people, including, for example, everyone living in a state in a case brought by that state’s attorney general.

The justices also specified two exceptions to its new rule: class-action lawsuits, which can apply to groups of people in a similar legal situation, and cases brought under the Administrative Procedure Act, which governs executive branch rule-making and allows judges to block actions by agencies found to be “arbitrary” or “capricious.”