An illustration of General Hassan Firouzabadi, head of Iran's armed forces, blocking the Straits of Hormuz
Iranian military exercises apparently emphasize three weapons in the strait: small suicide boats, mobile antiship cruise missiles, and sophisticated sea mines. Using these tools, how hard would it be for Iran to disrupt the flow of oil?
The answer turns out to be: very hard. Iran would have to disable many of the 20 tankers that traverse the strait each day -- and then sustain the effort. Iran cannot rely on the psychological effects of a few hits. Historically, after a short panic, commercial shippers adapt rather than give up lucrative trips, even against much more effective blockades than Iran could muster today.