In response to my question, “What common threat does [Roger] Cohen imagine would bind the U.S. and Iran together?”, Brien Jackson writes: “The Taliban. You’d think someone who fancies themselves an expert on Afghanistan would know that. But then, I suspect you probably did.”

I’m not sure whether I’m an expert on Afghanistan, but I know enough to realize that Iran doesn’t view the Taliban as a threat — certainly not as an existential threat (like Nazi Germany was to both the U.S. and U.S.S.R) that could drive Iran into America’s arms. Iran has a complicated history with the Taliban, having provided support to the Northern Alliance in the 1990s to fight the Taliban. Iran was also mildly helpful to U.S. efforts during the Bonn process in 2002 to set up a new, non-Taliban government in Afghanistan.

That was then, this is now. Today, Iran provides support to the Taliban. See, for example, this article in the Guardian of London, which reports:

British special forces operating on the border between Afghanistan and Iran have uncovered fresh evidence that Tehran is actively backing insurgents fighting UK troops.

Documented proof that Iran is supplying the Taliban with devastating roadside bomb-making equipment has been passed by British officials to Tehran, prompting fears that the war in Afghanistan may escalate into a regional armed conflict.

This is not an isolated instance. There is plenty more evidence — most of it classified — about links between Iran and the Taliban. The exact nature of the relationship isn’t clear, and it’s certainly not as close as the relationship between Iran and the Mahdist Army in Iraq or Hezbollah in Lebanon. But a relationship does exist notwithstanding the Taliban’s hardcore Sunni theology, which includes anti-Shiite prejudice. That should hardly be surprising since Iran backs other Sunni groups like Hamas. Tehran also has links with non-Muslim states like Venezuela and North Korea which, if anything, should be even more offensive to Muslim sensibilities.

But the mullahs have consistently shown a willingness to put theological purity behind geopolitical considerations. In this case, they do not want the U.S. to stabilize Afghanistan and turn it into a reliable pro-American ally — any more than they want to see us turn Iraq into a pro-American ally on their other border. It would be naive in the extreme to assume that Iran will put such considerations aside in the interests of greater harmony with the Great Satan.