(By R.K. Ramazani, the Edward R. Stettinius Professor Emeritus of Government and Foreign Affairs at the University of Virginia) After years of discussion, Iran’s nuclear agreement of July reached a turning point last week on Dec. 28. A Russian shipment carried almost all of Iran’s stockpile of low-enriched uranium out of the country, a major step toward implementing the nuclear deal struck last summer. For the first time in nearly a decade, Iran was left with too little fuel to manufacture a nuclear weapon.