Washington (CNN) The Supreme Court is poised to hear oral arguments in the travel ban case early next month. But that doesn't actually mean justices will ever decide the legality of President Donald Trump's controversial executive order.

The President's executive order makes clear that travel from six countries (Iran, Libya, Somalia, Sudan, Syria and Yemen) is suspended for 90 days while the secretary of Homeland Security and others submit a report on the results of a worldwide review.

The review is meant to identify what additional information will be needed from each foreign country to make sure that an individual seeking entrance is not a public-safety threat.

The Supreme Court -- responding to a lawsuits from states challenging the ban -- let much of the ban take effect in late June, meaning the 90-day clock started and will hit on or about September 24.

That date raises an important issue that could make the case moot or at the very least crowd out a substantive discussion on the legality of the travel ban. So far the debate has largely been about whether the executive order violates the Constitution or immigration laws. But that could change in the coming days.

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