It happened in April 1988, six months before the end of President Reagan's second term. A few days earlier, the foreign ministers of the United States, the Soviet Union and Pakistan, and a representative of Afghanistan, had met in Geneva to formally declare the end of the war in Afghanistan and initiate the withdrawal of Soviet forces from that country. This was a huge success of U.S. diplomacy, yet Pakistan's President Zia ul-Haq had a distinct view of what had happened in Geneva. During a phone conversation with Reagan, he said that while he was happy about the Geneva agreement, he had no intention to implement the condition to stop arming the mujahideen. When Reagan warned him that this would amount to lying to all parties, Zia responded: "We've been denying our activities there for eight years. Muslims have the right to lie in a good cause."

One wonders whether his self-serving statement about the right of Muslims to lie for a good cause is just a cheap excuse, or whether it is actually an ethical principle of Islam that can also be applied in politics and diplomacy. If the latter were the case, Iran may contemplate breaking the recent nuclear agreement at its convenience. This, in turn, would lead one to the conclusion that Iran, as a Muslim theocracy, cannot have the capacity to contract.

What about the meaning of the statement that Muslims have the right to lie for a good cause? The answer can be found in the Islamic principle of "taqiyya." Derived from the Quran, "taqiyya" originally permitted a Muslim to lie in three situations: in war, to settle disagreements, and in marital disputes. Over time, the application of "taqiyya" was broadened to cover more and more aspects of life. In practice, everyone who fears for his money, health or life is allowed to lie in order to avoid a disadvantage. For its proponents, "taqiyya" applies always and everywhere, even in matters of religion. The classic example for this was given by Ayatollah Khomeini himself: in 1981 he stated in public that in order to advance Iran's cause one was allowed to drink alcohol and lie.

This principle can only be understood in the context of Islam’s view of God. In contrast to Christianity, which proceeds from God as being infallible and just, in Islam Allah is "the best of deceivers." Several suras in the Quran contain such references (3:54, 7:99, 8:30, 10:21, 13:42, 27:50). If and when appropriate, Allah can and will have humans speak and act in order to deceive others. The implications of this are clear: if Allah is "the best of deceivers" who leads Islam's enemies astray, his adherents must do the same. The principle of "taqiyya" thus rests on firm ground and needs no special justification. Accordingly, for hundreds of years "taqiyya" has been religious dogma. Shiite Islam’s eleventh imam, Hasan al-Askari, said that a believer who does not practice "taqiyya" was "like a body without a head."

The principle of "taqiyya" constitutes not only a right but also a duty. In the eleventh century, Al-Ghazali, one of the most important Muslim jurists, offered the classic definition: "When it is possible to achieve such a praiseworthy aim by lying but not telling the truth, it is permissible to lie if attaining the goal is permissible… and obligatory to lie if the goal is obligatory." However, "taqiyya" does not only refer to the spoken word (i.e. lying) but also to action (i.e. betraying). Consequently, if acting truthfully would result in a disadvantage, there is a duty to cheat. Even more, if reaching a certain objective is paramount, lying and cheating become an outright duty.

What are the implications of the principle of "taqiyya" for international relations in general and for Iran's relationship with the secular Western democracies in particular? The answer can be found in the view of the world according to Islam, a view that has changed little in the past 1400 years. According to this view, the world is divided into the Muslim world and the world of the infidels. According to the Quran, the war between them will last "until all chaos ceases and all religion belongs to Allah" (8:39). This "eternal war" is being fought with all available means. Iran's current Supreme Leader, Ayatollah Ali Khamenei, made this crystal clear: in a 2004 speech he said, "Throw away your prayer chain and buy yourself a gun. For prayer chains keep you in stillness while guns silence the enemies of Islam. We know of no absolute values except total submission under the will of Allah the Almighty. The Christians and Jews say: 'Thou shalt not kill!' However, we say that killing comes close to the importance of prayer if need be. Deception, ambush, conspiracy, fraud, theft and killing are nothing but means for the sake of Allah." Peace is feasible only as a truce during a period of weakness of Islam, but even then everything below the threshold of war remains permitted. The Treaty of Quraysh is considered the model case for how to deal with such a period of temporary inferiority. In 628, Muhammad signed the Treaty with Mecca during a time of military exhaustion. Although the Treaty was supposed to last for ten years, Muhammad attacked Mecca after only two years, once he had managed to consolidate his military power.

The continuing relevance of this episode was demonstrated by Yasir Arafat. When he got heavily criticized for his peace agreement with Israel, he responded that for him this agreement was "no more than the agreement signed between our Prophet Muhammad and the Quraysh in Mecca." In other words, Arafat only entered into the agreement in order to abandon it once the Palestinians were in a more favourable position and could go on the offensive. In July 1988, Khomeini faced a similar situation. Given the disastrous military situation in the war with Iraq, he decided to unconditionally comply with UN Security Council Resolution 598 and agree to a ceasefire—to drink the poisoned chalice, as he called it. This war had made it clear to him that even though religious issues were paramount in Iran, the threat to the state's very existence warranted putting the interests of the state above the religious dogmas of Shiite Iran, at least temporarily. In a series of letters to President Khamenei and the Guardian Council, written in 1987 and 1988, Khomeini explained that the Government of the Islamic Republic could order the destruction of a mosque as well as suspend the five basic duties of Islam (confession of faith, prayer, fasting, donating to charity and travelling to Mecca), if this was in the state's interest. The highest aim was to ensure the survival of the Islamic Republic, as it was this unique state that could complete the Islamic Revolution.

Khomeini and his successors understood that, given the current global situation, Shiite Islam and the secular Western democracies are in a ceasefire. In such a phase, treaties with non-Muslims are possible, but they are only temporary and subject to "taqiyya": everything, in particular lying and cheating, is permitted in order to improve one's own situation.

This is the context for evaluating the nuclear deal with Iran. It justifies the prediction that throughout the ten-year duration of the agreement the Iranians will lie and cheat whenever possible in order to gain advantages or minimize disadvantages. In theory, this could even mean that Iran unilaterally abrogates the agreement, although this does not appear likely. What would make this step easier for them is the agreement's legal status: it is not a treaty under international law, but only a voluntary agreement that is legally binding. Thus, a simple statement by Iran would be sufficient to terminate the agreement.

However, the P5+1 do not seem worried by this prospect. Quite the contrary. Both President Obama and German Foreign Minister Steinmeier maintain that they had taken the possibility of Iranian cheating into account. Since it was prudent not to trust the Iranians too much, one had put great emphasis on verification and, moreover, had put in place an "ingenious" sanctions mechanism that, taken together, should effectively prevent cheating. Yet this approach has already failed, for it has not been possible to negotiate such an agreement. Rather, the agreement offers many loopholes for cheating. Only a few stubborn experts still maintain that the nuclear agreement with Iran is "waterproof" in the sense that it rules out Iranian violations.

The Iranians can relax. They have managed to conclude an agreement that is far more advantageous than they could have hoped for. Still, it should be clear that, according to the principle of "taqiyya," Iran will make use of every opportunity to quietly improve its situation even further. "Taqiyya" is something you don't talk about, but just do. Moreover, problems pertaining to Iranian compliance are being "solved" by referring to Khamenei’s 2004 fatwa according to which Iran will forever forego nuclear weapons. But this fatwa is in itself a case of applied "taqiyya," as it is a blatant lie. The permanent renunciation of nuclear weapons, which is usually traced back to Khomeini, was never serious. Shortly after the Islamic Revolution in 1979 Khomeini is said to have made some antinuclear statements, yet by the mid-1980s he demanded that Iran build nuclear weapons. A closer look also reveals that the evidence of the alleged 1979 fatwa is highly dubious. The sole source is a publication by U.S. journalist David Patrikarakos, referring to a conversation between Khomeini and Iran's ambassador at the IAEA, Ali Asghar Soltanieh. According to Soltanieh, Khomeini declared a fatwa in which he characterized nuclear weapons as "un-Islamic". Shortly thereafter, Soltanieh claims, he had translated the fatwa into English and sent it on Christmas cards to his IAEA colleagues in Vienna.