Mohammad Ayatollahi Tabaar explains how the Turkey's regional rise is torpedoing Iranian influence:
The Iranian government is aware of the ideological affinity between Iran's reformist opposition and the AKP [Turkey's ruling party]. Although they were born in diametrically opposed political systems, both strive to strike a balance between Islam and democracy. Iranian leaders fear that the AKP may inflict a similar damage to their legitimacy as the Iranian reform movement has. They acknowledge that the reformists, although defeated for now, managed to crack the heart of the establishment and bring many die-hard supporters of the regime to their side or neutralize them. Now, the AKP could create a similar legitimacy crisis for the Islamic government on a regional level, weakening Iran's soft power and undermining its popularity in the Muslim world.
Thomas P.M. Barnett notes another Turkish advantage over Iran: relative economic strength. Walter Russell Mead thinks the main beneficiary of the struggle between the two regional powers is the United States:
The US seeks a balance of power in the Middle East; that means its diplomacy can be flexible and work with any number of countries with varying political goals. Turkey is not challenging Iran to help the US, but the consequences of Turkey’s increased activism (widely seen as proof of US decline in the Middle East) are actually shoring up the foundations of US geopolitical interests in this critical part of the world. Indeed, the emergence of a healthy pluralism in the region, with a strong Egypt, Saudi Arabia, Iran, Turkey and others would tend on balance to make key US goals more achievable rather than less.
Agreed, which is why the neocon hostility to Turkey is so baffling (unless you assume that it's really about Israel's interests rather than the US's).
(Photo: Jordan Burroughs of USA (R) wrestles with Iran's Sadegh Saeed Goudarzi (L) during their Free Style 74 kg gold medal match at the Senior Wrestling World Championship in Istanbul, Turkey on September 17, 2011. By Mustafa Ozer/AFP/Getty Images)