It went virtually unnoticed (and unreported by this newspaper), but last week a federal court found the government of Iran liable for the 1998 bombings of the U.S. embassies in Kenya and Tanzania.

Wait, you say, wasn’t al-Qaeda responsible for the embassy bombings?

Al-Qaeda carried out the attack, but the U.S. District Court for the District of Columbia found that the bombings would not have been possible without “direct assistance” from Tehran as well as Sudan. “The government of Iran,” Judge John D. Bates wrote in his 45-page decision, “aided, abetted and conspired with Hezbollah, Osama Bin Laden, and al Qaeda to launch large-scale bombing attacks against the United States by utilizing the sophisticated delivery mechanism of powerful suicide truck bombs.”

Iran’s assistance was not peripheral to the plot, Bates found. “Al Qaeda desired to replicate Hezbollah’s 1983 Beirut Marine barracks suicide bombing, and Bin Laden sought Iranian expertise to teach al Qaeda operatives about how to blow up buildings,” Bates wrote. “Prior to their meetings with Iranian officials and agents Bin Laden and al Qaeda did not possess the technical expertise required to carry out the embassy bombings in Nairobi and Dar es Salaam. The Iranian defendants, through Hezbollah, provided explosives training to Bin Laden and al Qaeda and rendered direct assistance to al Qaeda operatives . . . [I]n a short time, al Qaeda acquired the capabilities to carry out the 1998 Embassy bombings, which killed hundreds and injured thousands by detonation of very large and sophisticated bombs.”

These facts are worth some reflection in light of a report released this week by Tom Donnelly, Danielle Pletka and Maseh Zarif, my colleagues at the American Enterprise Institute (AEI), on the tremendous difficulties of “Containing and Deterring a Nuclear Iran.” They warn that Iran could very well have a weaponized nuclear capability when the next president takes office in January 2013. Imagine what this means. If Iran helped al-Qaeda attack the United States without a nuclear umbrella to protect it from retaliation, what might the regime do once it possesses nuclear weapons?

Even without nuclear weapons, Iran has been difficult to deter. Iran was almost certainly behind the 1996 attack on the Khobar Towers in Saudi Arabia that killed 19 U.S. airmen. Tehran has provided training and lethal bomb-making equipment to insurgents in Iraq, including “explosively formed penetrators” capable of breaking through the thickest armor in American military vehicles. And to this day, Iran continues to cooperate directly with al-Qaeda’s senior leadership.

Five months ago, the Obama Treasury Department named six al-Qaeda facilitators operating in Iran under a “secret deal” between al-Qaeda and the Iranian regime. “This network serves as the core pipeline through which al-Qa’ida moves money, facilitators, and operatives from across the Middle East to South Asia,” the Treasury Department said.

One of the key operatives in this Iranian al-Qaeda network was Atiyah Abd al-Rahman. Rahman was the operational commander of al-Qaeda (the same position held by Khalid Sheik Mohammed when he planned the Sept. 11 attacks) and following bin Laden’s death rose to become al-Qaeda’s second in command before being killed himself in August. As David Ignatius reported this year, most of the documents found in bin Laden’s compound were communications between bin Laden and Rahman, who was bin Laden’s link to the outside world, including plans for an attack on the United States that “would match, if not outdo, the impact of 9/11.”

So until he was killed a few months ago, Iran was working directly with al-Qaeda’s operational commander — a terrorist with whom bin Laden was plotting to outdo the destruction of the Sept. 11 attacks. Of course, the obvious way to outdo that destruction is to use a nuclear weapon. Would Iran share nuclear weapons with al-Qaeda? Iran was willing to help al-Qaeda blow up two American embassies using conventional explosives. With a nuclear arsenal to deter American retaliation, what is to stop it from helping al-Qaeda carry out a far-deadlier attack using a weapon of mass destruction? As the AEI report notes, “It is likely that the Iranians value nuclear weapons not only for their deterrent purposes but also, if delivered by a suicide terrorist, for the intoxicating promise of devastating effect and potential deniability.”

Even if Iran were unwilling to risk aiding al-Qaeda with such an attack, a nuclear umbrella could embolden the regime to carry out what Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, has called a “Beirut-like moment” in an effort to drive the United States out of the region. Think about the audacity of Iran’s actions in facilitating al-Qaeda’s bombings of two U.S. embassies in 1998, and imagine how hard it will be to deter the regime from similar attacks once it has the bomb.