Reality: If the Iranians block the Strait of Hormuz, the United States will initiate a broad military offensive against specific targets in Iran -- conversely, if the U.S. or Israel bombs Iran's nuclear facilities, Iran will block the narrow strip of water separating Iran from Oman.
Question: What will happen if Iran merely says that they've mined the Strait of Hormuz? It'd be enough to stop all big oil tanker traffic. But would this trigger a U.S./Israeli military response simply because we might be looking for a justifiable cause to bomb their nuclear facilities?
To better understand this, read:
The Week Weekly Magazine:
Strait of Hormuz
A Threat Assessment in the Strait of Hormuz