In July 2012, a suicide bomber attacked a bus carrying Israeli tourists in Bulgaria. Five Israelis were killed -- along with their Bulgarian driver -- and a Bulgarian investigation established links between the bomber and the pro-Iranian Lebanese group Hezbollah.
So the most important question of all is: When does America give up on diplomacy with Iran?
Iran is different from other Middle East countries in an important way. For decades, the United States propped up Arab leaders and had, on the surface anyway, warm relations with them. But almost universally, the man in the street detested the U.S. government.
In Iran, it's the man on the street who is largely supportive of America. It's the government and the extremists it trains that have all the hatred for what the U.S. represents.
Perhaps the question right now isn't about giving up, but whether it's time to double down on diplomacy to avoid a conflict that poses serious and unpredictable consequences.