RICHMOND, Va. -- A challenge to President Donald Trump's revised travel ban appears to hinge on whether a federal appeals court agrees that the Republican's past anti-Muslim statements can be used against him.

For over two hours a panel of 13 judges from the 4th Circuit grilled lawyers from the Justice Department and the ACLU about the legality of the president's revised travel ban, CBS News' Paula Reid reported.

The 4th U.S. Circuit Court of Appeals wrestled Monday with whether the court should look beyond the text of the executive order to comments made by Trump and his aides on the campaign trail and after his election in order to determine whether the policy illegally targets Muslims.

"That's the most important issue in the whole case," said Judge Robert King, who was appointed to the court by President Bill Clinton.

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The 13 judges peppered both sides with tough questions but gave few clues as to how they might rule. The judges did not immediately issue a decision on Monday.

A federal judge in Maryland who blocked the travel ban in March cited Trump's comments as evidence that the executive order is a realization of his repeated promise to bar Muslims from entering the country.

The administration argues that the court shouldn't question the president's national security decisions based on campaign promises.

"This is not a Muslim ban. Its text doesn't have to anything to do with religion. Its operation doesn't have anything to do with religion," Acting Solicitor General Jeffrey Wall told the appeals court.

The countries were chosen because they present terrorism risks and the ban applies to everyone in those countries regardless of religion, Wall said. Further, the banned countries represent a small fraction of the world's Muslim-majority nations, lawyers for the administration say. Wall, according to Reid, also argued that the president wanted time to review vetting procedures, although he admitted the government has not been able to fully assess those procedures because of the obstacles posed by litigation.

Omar Jadwat, an attorney for the American Civil Liberties Union, noted that Trump had called for a "total and complete shutdown" of Muslims entering the U.S. remained on his campaign website even after he took office. That call, which was still online earlier Monday, appeared to have been taken down by the afternoon hearing.

Jadwat claims the administration has failed to provide a legitimate national security reason for the policy.

"The order is completely unprecedented in our nation's history," Jadwat said.

Several judges expressed skepticism about the idea that the court would blind itself to Trump's comments about Muslims.

"Don't we get to consider what was actually said here and said very explicitly?" asked Judge James Wynn Jr., who was appointed by President Barack Obama.

Another judge said he was worried about the idea of a court opening the door to using a president's past to evaluate the constitutionality of a policy.

"Can we look at his college speeches? How about his speeches to businessmen 20 years ago?" asked Judge Paul Niemeyer, who was tapped by President George H.W. Bush.

The first travel ban in January triggered chaos and protests across the country as travelers were stopped from boarding international flights and detained at airports for hours.

After a three-judge panel of the 9th U.S. Circuit Court of Appeals refused in February to let the travel ban take effect, the administration tweaked the order and issued a new one.

The new version made it clear the 90-day ban covering those six countries doesn't apply to those who already have valid visas. It removed language that would give priority to religious minorities and erased Iraq from the list of banned countries.

But critics said while the new executive order impacts fewer people, it remains a realization of Trump's promised Muslim ban and cannot stand.

The ACLU and National Immigration Law Center brought the case on behalf of several organizations, as well as people who live in the U.S. and fear the executive order will prevent them from being reunited with family members from the banned countries.

Elite universities, democratic attorneys general and former foreign policy and national security officials like ex-Secretary of State Madeleine Albright called on the court to block the travel ban.

Meanwhile, a group of 12 state attorneys general and the governor of Mississippi argued that the action is not a "pretext for religious discrimination" and should be allowed to take effect.

Attorneys for the president likely see the moderate 4th Circuit as friendlier territory than the 9th Circuit, which conservatives have long accused of being too liberal. Three 9th Circuit judges appointed by Clinton are scheduled to hear a more-sweeping challenge to Trump's revised travel ban next week.

While the 4th Circuit was long considered one of the most conservative appeals courts in the country, it moved to the center under Obama, who appointed six of the 15 active judges.

Two Republican-appointed judges - Judge Allyson Duncan and Judge J. Harvie Wilkinson III - didn't hear the travel ban case. Wilkinson's daughter is married to the acting solicitor general. It was not immediately clear why Duncan was recused.

CBS News' Paula Reid contributed to this report