"There isn't an American embassy to attack," he says. "If you've got a shadow war going on with Israel and the United States, in which people are getting killed and bombed, and facilities are getting attacked, and then they put more pressure on you through the [United Nations' nuclear watchdog agency] and the EU and US sanctions – well, you lash out."
The response was severe: Britain shut down the Iranian Embassy in London and expelled Iran's diplomats; the European Union slapped sanctions on 180 more Iranian entities and people; and the US Senate voted unanimously in favor of sanctions against all who do business with Iran's central bank.
Those were predictable results, but they are leading to an unpredictable endgame. And they fit a long-established pattern that stretches back to 1979, when militant students – acting without the knowledge or even the tacit approval of Iran's revolutionary leader, Ayatollah Ruhollah Khomeini – seized the US embassy.
Khomeini later endorsed the move, which was aimed at liberals in the fledgling government but also helped forge a generation of mutual US-Iran hostility.
"It is common for competing groups to sacrifice national interests – such as Iran's international credibility – to achieve their own goals," writes Mehdi Khalaji, an Iran expert at the Washington Institute for Near East Policy, in a recent analysis.