Six years into the crisis in Syria, Iran sees the outcome of the conflict as shaping the new Middle East. It was Iran’s first overt foreign intervention in decades, one that some Iranian ideologues have called a war for existence. Iranian officials say it spared the Islamic Republic from having to fight a similar war within its own borders. Yet it has been costly, draining and merciless in terms of material losses, and even worse when it comes to Iran’s image in the Muslim world. It has limited Iran’s options and has caused alliances — notwithstanding the common ground Iran shares with its partners — to seem very shaky and fragile.

“Iran learned a lot from these years,” an Iranian military source told Al-Monitor on condition of anonymity. The source said the conflict in Syria has not been a traditional war where things can easily be anticipated: “The mandate was changing from one day to another. When Iran decided to take part in the war via our military advisers, Syrian President Bashar al-Assad was on the verge of falling. More than 70% of the country was under [the control of] terrorist groups who were enjoying widespread international, regional states’ and popular support. Today, President Assad has the upper hand, and the world knows well that he’s the only choice for those who seriously want to defeat terrorism. Yet this is not the final phase.”

In Tehran, political and military elites believe enemies of the “resistance axis” created the crisis in Syria to take revenge for what Iranian elites see as the latter’s achievements and widespread popularity in the region. “It’s obvious that after the 33-day war in Lebanon and Hezbollah’s victory over Israel [in 2006], the Americans and their local agents started thinking of how to defeat us,” an Iranian official told Al-Monitor on condition of anonymity. The official said, “Since they can’t wage a war on Iran and their attempt to destroy Hezbollah failed, there was only one option at that time left — hitting the heart: Syria.” Therefore, according to the Iranian official, the Islamic Republic had no choice but to defend itself, and therefore, “Iran’s struggle in Syria is different from others: It’s an existential war with no choice for us but to win. All the other parties fighting in Syria can afford to win or lose, save Iran. Not winning this war will have dire consequences not only for Iran but for the Shiites of the world. Therefore, it was the Supreme Leader Ayatollah Ali Khamenei who took the decision to help Syria. It was both a religious and a political decision.”

The story of the Iranian decision to intervene in Syria has been a question for many, mainly with regard to how the decision was taken and whether a plan was in place from day one. Filling out the picture is the account of former Iranian member of parliament Esmail Kowsari — a former commander in the Islamic Revolutionary Guards Corps (IRGC) — who told the semi-official Fars News Agency in November 2013 how Hezbollah chief Hassan Nasrallah had gone to Ayatollah Khamenei with fears that Assad would be toppled. Kowsari said that Nasrallah, nine months after the Syrian war started, had concluded that the situation was bad and was almost over. Nasrallah was quoted as saying, "Along with some officials, we went to the [supreme] leader and told him our thoughts. After we finished speaking, he said: ‘No, that is not the case. We must just do our duty. If we do our duty, Assad and Syria will be stable.'”