Trump nuclear talks face defining question: What happens to Iran’s uranium stockpile?

Even as U.S. and Iranian negotiators reportedly move toward a temporary framework agreement, one of the most consequential questions remains unresolved: What happens to Iran’s enriched uranium stockpile?

Iranian officials repeatedly have insisted retaining enriched uranium is a red line in negotiations, even as President Donald Trump has vowed Iran "will not have a nuclear weapon" and suggested the United States could ultimately "take" the material if necessary.

Nonproliferation experts...