It was the Iraqi army, backed by the US, that kept Khomenei from over-running the Persian Gulf, something he swore he would do.
Never mind that the radical Shiites of Iran are sworn enemies of the Sunni fundamentalists of Al Qaeda.
This a truism that passes for wisdom, but is actually quite overdone.
Iran opposes the Sunni regimes, but Iran's Shia insurgents and the Sunni insurgents in Lebanon and the West Bank manage to agree to both attack Israel. Iran and Iraq and Saudi Arabia all support Arafat, and it was a ship full of weapons from Iran that was seized recently headed for Gaza. Iran opposed the Taliban, and supported the Northern Alliance, but has also provided refuge to Al Qaeda. And has helped to fund Al Qaeda operations.
Hardly had the Taliban collapsed when a new war was declared, a war on terror with a long list of enemies (almost none of them related to Al Qaeda) and no obvious endgame.
The war was only incidentally against the Taliban, in that our real target was Al Qaeda. And who is Al Qaeda? That is the Muslim insurgency funded and managed from Riyadh. Osama Bin Ladin was their titular leader, but his movement was funded by the Saudis, and facilitated by both Iran and Iraq. They were active in Chechnya, Chinese Turkestan, the Phillipines, and Indonesia. Some of their people have recently taken refuge in Georgia, Iran, and Iraq itself.
Look where we are sending our soldiers and it dovetails quite nicely with the list of countries where Al Qaeda is operating.
In other words, Katz is prevaricating.