President Donald Trump could pursue a variety of legal strategies, now that the U.S. Court of Appeals for the Ninth Circuit has upheld a ban on his executive immigration order, Professor Anil Kalhan told ABC News on Feb. 10.

“This opinion is a narrow one, but forceful," Kalhan said. “The Republican administration faces an uphill road if it wants to appeal this order in the short term, but there is a lot litigation left to come before this is definitively resolved.”

The administration faces a short deadline for seeking a reconsideration of the appeals court ruling, either by the same three judges or by an “en banc” panel of 11 judges from the Ninth Circuit.

The latter scenario is unlikely, Kalhan said, explaining that 13 out of the 25 judges in the circuit would have to agree to an “en banc” review.

With the executive order facing challenges in a number of jurisdictions, different federal district courts and appeals courts may produce conflicting rulings, which would provide a basis for asking the Supreme Court to review the matter, Kalhan said.

A Feb. 10 Reuters article citing Supreme Court Justice Anthony Kennedy’s reasoning in a 2015 immigration case explored the possibility that he would be skeptical of Trump’s ban, which restricts travel to the U.S. by people in seven Muslim-majority countries.

The article noted that Kennedy had written a concurring opinion that said the U.S. government’s motives for denying someone entry can sometimes be subject to legal review.

Kalhan said, however, that Kennedy’s opinion could be subject to diverse interpretations and might not predict his response, should the executive order come before the Supreme Court.  

In an article published by the Mexican newspaper El Universal on Feb. 6, Kalhan noted that the chaos surrounding Trump’s immigration initiatives has sparked widespread uncertainty that will fuel extensive litigation.

There will be a lot of litigation in courts, things like sanctuary cities will most likely reach the Supreme Court, and there are more: litigation on expedited deportations, or filed by those affected with the construction of the wall,” Kalhan predicted. “This administration will be very busy for four years defending in court everything that it decides to do.”