A decision isn't expected to be imminent, one source said, but debate within the administration has shifted recently to more deeply exploring how and when the act might be invoked.

Talk inside the White House about invoking the act has ebbed and flowed since Trump took office again in January, said the five people, who include the senior administration official, two people familiar with the discussions and two people close to the White House.

But the debate inside the administration has shifted recently, from whether it makes sense to invoke the act to more deeply exploring how and when it might be invoked, both people close to the White House said.