Rational does not mean reasonable. It means that the regime wants to thrive and, given that goal, it calculates costs and benefits and acts accordingly. But it is worth asking a broader question as well: Is Iran being reasonable? Are Tehran’s actions an understandable response to its geopolitical situation? At a Time Warner public conversation last week, former secretary of state James Baker remarked that the key to success in negotiations is to put yourself in your adversary’s shoes and see the world from that perspective.

Look at a map of the Middle East. Shiite Iran is surrounded by hostile Sunni states. Across the Persian Gulf sits Saudi Arabia, its fanatically anti-Shiite and well-armed archenemy . (Last year, Saudi Arabia was the largest weapons importer on the planet.) In Iraq and Syria, Iran faces large Sunni insurgencies dedicated to slaughtering the Shiites. Add to this the nuclear dimension. Iran has several nuclear-armed neighbors — Pakistan, India, Russia, China and Israel.

Plus, Iran has faced active opposition from the world’s superpower for more than three decades. When Iraq attacked Iran shortly after the Islamic revolution, the United States quietly supported Saddam Hussein, even as he used chemical weapons against the Iranians.