The motorcycle bomb that assassinated Massoud Ali Mohammadi, an Iranian nuclear-physics professor, highlights just how vulnerable the regime is becoming. There could be any number of motives, but it’s reasonable to suspect that Professor Ali-Mohammadi was killed for his involvement in the nuclear issue. Some opposition groups may claim that they have penetrated the nuclear program. This is an exaggeration. Far more likely, Iranian officials — even in sensitive organizations — are becoming so corrupt that information can be bought. The hit will also send a chill down the spine of other scientists who must now consider whether they want to work for the losing side. Of course, many of these Iranian nuclear scientists will also realize that they will have lucrative jobs in their fields should the regime fall, as a post-Islamic Republic of Iran will likely maintain an advanced nuclear program.