The court led by Chief Justice John G. Roberts Jr. over the last two decades has not been known for its modesty or caution. Its signature move has been bold assertions of power backed by sweeping claims about the meaning of the Constitution.

It gutted campaign finance laws and the Voting Rights Act, overturned the constitutional right to abortion, did away with affirmative action in higher education and adopted a new interpretation of the Second Amendment that protects an individual’s right to own guns.

But as the first wave of challenges to President Trump’s blitz of executive orders has reached the justices, a very different portrait of the court is emerging. It has issued a series of narrow and legalistic rulings that seem calculated to avoid the larger issues presented by a president rapidly working to expand power and reshape government.

On Monday, the court ruled that Venezuelan migrants who challenged the administration’s plans to send them to a notorious prison in El Salvador had filed their lawsuits in the wrong court, without ruling on the underlying legal issues.

The justices’ new approach appears to have multiple goals: to stay out of the political fray, to maintain their legitimacy and, perhaps most important, to avoid a showdown with a president who has relentlessly challenged the legitimacy of the courts.

Mr. Trump, for his part, has called for the impeachment of judges who ruled against him and has suggested on social media that courts are powerless to tell him what to do. “He who saves his Country does not violate any Law,” he wrote.