State Attorney General Bob Ferguson brought Washington's suit with Minnesota against the president over the immigration order, leading a federal judge to put a temporary block on the order on Feb. 4, a ruling that was upheld last week by a federal appeals court.
Asked by ABC News Chief Anchor George Stephanopoulos on "This Week" on Sunday whether he would try to depose President Trump in the case, Ferguson said, "I won't announce that on national TV. But, I can assure you of this: I want to be crystal clear with your viewers. My job as attorney general is to uphold the rule of law in this country. And I’ll use every tool that I have as attorney general to make sure that the president follows that Constitution."
Ferguson also said he and others working on the case "can seek depositions from administration officials. We can ask for documents and emails to get behind what truly motivated that executive order."
On Thursday, the Ninth Circuit Court of Appeals upheld the Feb. 4 ruling by a federal judge putting a temporary restraining order on President Trump's executive action that temporarily bars entry into the U.S. of people from seven Muslim-majority countries.
Shortly after the appeals court released its decision, Trump took to Twitter, writing, in all caps, “SEE YOU IN COURT, THE SECURITY OF OUR NATION IS AT STAKE!”
Stephanopoulos asked Ferguson if President Trump is in a "very strong position" in the case considering that a federal law, 8 U.S. Code 1182, states, "Whenever the president finds that the entry of any aliens or of any class of aliens into the United States would be detrimental to the interests of the United States, he may by proclamation, and for such period as he shall deem necessary, suspend the entry of all aliens or any class of aliens as immigrants or nonimmigrants, or impose on the entry of aliens any restrictions he may deem to be appropriate."
"We recognize that," Ferguson said. "But there's another document that the president is not reading from and that's the Constitution."
"Folks have rights of due process, for example," he said. "Nobody is above the law. An executive order is still, must be consistent with our Constitution."
Stephanopoulos also asked about Washington's case relying on comments by Trump and his allies during the campaign about a Muslim ban.
Noting that Trump "now denies that this is a Muslim ban," Stephanopoulos asked, "Is there really any precedent for using campaign statements to establish" motive?
Ferguson said there is precedent for looking at statements by people who put an executive order in place if "if you're looking for an improper motive, which we're certainly asserting. So we will absolutely continue to use those statements."