The Iranian government steams that the West doesn't respect 4,000 years of Persian culture. Neither, one can argue, does the current harsh clerical leadership and corruptly elected government in Tehran.

The leadership, through the various thuggish branches of its security forces, has jailed, beaten or driven into exile countless writers, poets, playwrights, filmmakers and writers for not espousing the clerics' joyless brand of Islam.

To most of the West, modern Iran began with the 1979 takeover, supposedly by patriotically motivated "students," of the U.S. embassy in Tehran, where 52 hostages were held for 444 days.

On Tuesday, there was new evidence that the Iranian leadership had learned nothing from that experience except that they were safe as long as they were willing to be an international pariah.

While police stood by, a mob of protesters stormed the British embassy and an embassy housing complex, setting fires, vandalizing property, destroying files and, bizarrely, making off with a portrait of Queen Elizabeth.

The mob takeover was ostensibly in response to British support for U.S.-backed stepped-up sanctions aimed at convincing Iran to abandon a nuclear weapons program. In fact, it seemed more indicative of deep divisions among Iran's clerical and civilian leadership.

The protesters had hoped to force President Mahmoud Ahmadinejad to evict the British ambassador, and, indeed, very quickly the parliament, which answers more to Supreme Leader Ayatollah Ali Khamenei, voted to order the departure of the ambassador and the withdrawal of their own envoy from London.

Tehran's erratic conduct comes against a backdrop of increasingly belligerent Iranian missile threats to its neighbors. The Iranians, like the Russians, are dismayed by the NATO missile shield under construction in Eastern Europe and Turkey.

The Russians could easily overwhelm the shields and many of their objections seem like mere posturing. But the shield does represent a real deterrent to Iran's missiles.

Over the weekend, the senior commander of Iran's Revolutionary Guard, said, "Should we be threatened, we will target NATO's missile defense shield in Turkey and then hit the next targets," those being Israel and U.S. interests, such as military bases in the Middle East.

The danger is that a divided government that would do something stupid like attack the British embassy, in violation of long established international law and custom, might do something even more stupid.