NEW You can now listen to Fox News articles! 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 say the issue sits at the center of whether any future agreement can credibly prevent Iran from rapidly moving toward weapons-grade enrichment — particularly after U.S. strikes damaged key nuclear facilities but did not necessarily eliminate the nuclear material itself.…