But several judges have argued that campaign promises should be off-limits, or at least dwarfed by government actions that are not overtly discriminatory.
"Opening the door to the use of campaign statements to inform the text of later executive orders has no rational limit," Judge Paul Niemeyer wrote in dissent to the 4th Circuit decision. He mused that such past history could extend to "statements from a previous campaign, or from a previous business conference, or from college."
Judges in California, Hawaii, Maryland, Massachusetts, Virginia and Washington have weighed in on the question this winter and spring, raising a number of issues that are likely to come before the Supreme Court as soon as later this month.
The majority of them have said courts can and should examine the purpose behind government actions; that Trump's words reveal his purpose to be, at least in part, banning Muslims; that his initial focus on Iran, Libya, Somalia, Sudan, Syria and Yemen is but a means to that end; and that Trump the president cannot claim to be different than Trump the candidate.
"Just as the Supreme Court has held that 'the world is not made brand new every morning,' a person is not made brand new simply by taking the oath of office," said Judge Leonie Brinkema of the U.S. District Court for the Eastern District of Virginia.
Her reference was to a Supreme Court ruling in 2005, in which Justice David Souter wrote that two Kentucky counties could not hide the unconstitutional religious purpose of their Ten Commandments courthouse displays by later adding additional documents.
"Reasonable observers have reasonable memories," Souter wrote. "Our precedents sensibly forbid an observer 'to turn a blind eye to the context in which the policy arose.'"
But Mathew Staver, who represented the two counties before the Supreme Court, says the original display and later versions all represented government actions. "Here, you have comments by the president before he was president," Staver says. "That is fundamentally different."