Economic and diplomatic relations between Iran and Turkey have improved significantly in recent years, and for good reason. Each side offers something the other needs. Turkey needs oil and gas for its growing economy and a market for its export products. Iran is Turkey's second-largest supplier of natural gas and is eager to buy many Turkish products. Iran also needs trade partners who are willing to ignore American and international sanctions to sell it the products others won't. Turkey has done just that, ignoring the sanctions selectively and periodically. In 2010, for example, Turkey exported gasoline to Iran at a time when other exporters were canceling their fuel export deals with Iran to avoid the wrath of the United States.
These beneficial trade relations, along with the rise of Islamic parties in Turkey, have, up to now, encouraged both countries to downplay their ideological and strategic disagreements. The recent developments in Syria, however, will test the limits of Turkish-Iranian ties in the coming months. Turkey has grown more critical of Damascus in recent weeks and has accepted thousands of refugees fleeing the instability in Syria.
The Islamic government of Iran, on the other hand, has remained an active and vocal supporter of President Bashar al-Assad's administration. It has accused the Syrian opposition of serving the interests of the U.S. and Israel and, in turn, has been accused by those countries of helping the Syrian government conduct surveillance and repression of opposition groups.