By Aaron Kliegman\u00a0 When Joe Biden was vice president,\u00a0the US had an obsession:\u00a0establishing\u00a0friendlier relations with Iran through\u00a0diplomacy \u2014\u00a0specifically,\u00a0a nuclear deal.\u00a0This obsession dominated the Obama administration\u2019s approach to the Middle East,\u00a0superseding\u00a0all other concerns.\u00a0Biden\u00a0may try to revive this agenda\u00a0as president, but he\u2019d\u00a0be\u00a0wrong\u00a0for doing so\u00a0\u2014 as a\u00a0recent assassination makes clear.\u00a0 Over the weekend, the\u00a0New York Times\u00a0reported\u00a0that, \u201cat the behest\u201d of the US,\u00a0Israeli operatives killed al Qaeda\u2019s second-highest leader,\u00a0Abu Muhammad al-Masri,\u00a0in Iran on Aug. 7.\u00a0According to the\u00a0article,\u00a0two assassins on a motorcycle fatally shot\u00a0al-Masri\u00a0as he was driving in the streets of Tehran, the Iranian capital.\u00a0 Other\u00a0media\u00a0outlets later\u00a0confirmed\u00a0the\u00a0report, noting that Israel and America worked together\u00a0to track and kill\u00a0al Qaeda\u2019s No. 2.\u00a0Reportedly,\u00a0al-Masri\u00a0was\u00a0planning\u00a0attacks on Jewish and Israeli targets around the world at the time of his death.\u00a0 The most\u00a0important detail\u00a0of this\u00a0story is its location.\u00a0According to conventional wisdom,\u00a0al Qaeda\u2019s\u00a0second in command\u00a0shouldn\u2019t have\u00a0been\u00a0in Iran.\u00a0 \u201cIran, a Shiite Muslim theocracy, and\u00a0al Qaeda, a Sunni Muslim jihadist group, have fought each other on the battlefields of Iraq and other places,\u201d\u00a0reported\u00a0the\u00a0Times, which\u00a0described Iran and al Qaeda as \u201cbitter enemies.\u201d\u00a0 Many analysts and politicians, especially those on the\u00a0political left\u00a0and the\u00a0isolationist-leaning right,\u00a0assert that\u00a0Iran and al Qaeda\u00a0have\u00a0never cooperated in any significant way.\u00a0How could they? After all, they\u2019re ideological rivals.\u00a0\u00a0 And yet,\u00a0al-Masri\u00a0was living freely in an upscale suburb of Tehran.\u00a0It\u00a0turns out that\u00a0Iran and al Qaeda are perfectly willing to cooperate against their common enemies: America and Israel.\u00a0 Of course, both sides have openly fought each other in places such as Syria and Yemen. But nonetheless, Iran and al Qaeda formed a\u00a0complicated\u00a0alliance\u00a0that\u00a0dates back to the early 1990s, when both sides began a decades-long collaboration\u00a0that continues today.\u00a0\u00a0 The\u00a0evidence\u00a0is\u00a0ample\u00a0\u2014\u00a0and irrefutable.\u00a0According\u00a0to the 9\/11 Commission Report, for example, Iran and its chief proxy, Hezbollah, gave al Qaeda the \u201ctactical expertise\u201d it needed to carry out\u00a0the\u00a0devastating\u00a01998\u00a0attacks on US embassies in\u00a0Africa \u2014 attacks that\u00a0al-Masri\u00a0helped plan and that landed him on the FBI\u2019s Most Wanted Terrorist list.\u00a0 The\u00a0partnership evolved from there, especially after 9\/11 and the fall of the Taliban in Afghanistan. Senior leaders of al Qaeda fled to Iran, where they ultimately reached an\u00a0agreement with the Iranian regime. The\u00a0Treasury Department described\u00a0this arrangement well\u00a0in 2012.\u00a0\u00a0 \u201cUnder the terms of the agreement between al Qaeda and Iran,\u201d the department\u00a0reported, \u201cal Qaeda must refrain from conducting any operations within Iranian territory and recruiting operatives inside Iran while keeping Iranian authorities informed of their activities.\u201d\u00a0\u00a0 In return, Treasury continued, \u201cthe\u00a0government of Iran gave the Iran-based al Qaeda network freedom of operation and uninhibited ability to travel for extremists and their families.\u201d\u00a0 Documents recovered at Osama bin Laden\u2019s compound in Pakistan affirmed this deal,\u00a0detailing\u00a0how Iranian intelligence provided safe haven to members of al Qaeda, facilitated travel of some operatives, and even offered money, arms, and training to the terrorist group.\u00a0 Al Qaeda benefited immensely from\u00a0Iran\u2019s support.\u00a0Just read\u00a0a\u00a0letter\u00a0from October 2007 to an unknown jihadist\u00a0called \u201cKarim.\u201d The letter, which analysts\u00a0believe\u00a0was most likely written by bin Laden, explains that Iran was al Qaeda\u2019s \u201cmain artery for funds, personnel, and communication, as well as the matter of hostages.\u201d\u00a0 All of this begs obvious questions.\u00a0Why should the US try to establish friendlier relations with a regime that supports those responsible for 9\/11? Why should we consider lifting sanctions on a country whose\u00a0government\u00a0helped\u00a0al Qaeda rebuild itself?\u00a0Why should we be OK with such a murderous, anti-American theocracy building a nuclear infrastructure?\u00a0 These are good questions to ask Biden, who\u00a0wants\u00a0to return to the nuclear deal with Iran.\u00a0 To\u00a0paraphrase\u00a0former\u00a0Secretaries of\u00a0State George Shultz and Henry Kissinger, the nuclear deal concedes\u00a0the capability that it was supposed to\u00a0prevent:\u00a0Iran\u2019s ability\u00a0to develop a nuclear arsenal. All the deal does is\u00a0delay\u00a0this nightmare for about a decade \u2014 while giving Iran billions of dollars\u00a0by lifting sanctions in the\u00a0meantime.\u00a0\u00a0 Perhaps Biden would demand as part of a renegotiation that Iran cut all ties to al Qaeda. All evidence, however, points to\u00a0him making\u00a0endless concessions in hopes of\u00a0reviving the deal.\u00a0\u00a0 A Biden administration would be staffed largely by alumni of the Obama administration, which saw the nuclear deal as the\u00a0vehicle\u00a0to begin\u00a0moderating\u00a0the Iranian regime and\u00a0creating\u00a0a\u00a0new equilibrium in the Middle East\u00a0under which\u00a0Iran and America\u2019s allies \u201cshare\u201d the region.\u00a0 Iran\u2019s leaders are well aware of this fact, which is in part why they\u2019re\u00a0continuing\u00a0to\u00a0violate\u00a0the nuclear deal\u00a0egregiously.\u00a0They clearly\u00a0think\u00a0they can pressure a Biden administration to negotiate a new deal favorable for Iran,\u00a0believing\u00a0Biden and his team would do everything possible to avert a crisis and possible conflict.\u00a0 The leaders of Iran are probably right. They\u2019re not stupid, just evil \u2014 evil enough to support those responsible for 9\/11.\u00a0 Indeed, calling Iran the world\u2019s foremost sponsor of terrorism isn\u2019t a talking point; it\u2019s the truth.