It was May 2015 when a Turkish journalist asked President Recep Tayyip Erdoğan about Iraqi Kurdistan possibly deciding to declare independence. Erdoğan said, "This is something that should be treated as Iraq's domestic affair. If Iraq, internally, decides to partition a state, this is an internal issue for them." Turkish media largely interpreted this as a green light to an independent Kurdistan at the time.

Two years later, Erdoğan now says he is saddened by the Iraqi Kurdistan Regional Government's (KRG) decision to go to a referendum on independence. "This is a wrong step. We hope that this step is taken with consultation, as we did in the past. This is not beneficial for anyone at this critical juncture," he said, mirroring a U.S. State Department statement on the issue.

Why the change of heart?

First, Turkey's own domestic policies play a large role in this attitude. There was a functioning peace process between Turkey and the U.S. and E.U.-designated terror group, the PKK in 2015. But in the course of just two months, the PKK decided to end the ceasefire, and urban warfare against the Turkish security forces followed.

Secondly, the PKK's Syrian arm, the Democratic Union Party (PYD), extended its territories along the Turkish border, and has now reached deeper into the south, to Raqqa. Before the collapse of the cease-fire, the People's Protection Units (YPG) was manageable trouble for Ankara. But now with the YPG getting even stronger U.S. backing, the YPG now controls large swathes of territory and they dream about creating a semi-independent state.

All these points are interconnected, partly because Ankara's own policy of promoting the KRG President Masoud Barzani as a mediator in its own peace process. Turkey is also leveraging Barzani's animosity toward the PKK and the YPG in a manner that suits its national interests.

However, in all fairness, one also must see that Kurdistan reached this "independence threshold" thanks to Turkey's energy policies in Iraq.

A report published by the Atlantic Council last week, "An Independent Actor: Turkish Foreign and Energy Policy Toward Russia, Iran, and Iraq" summarizes how Turkish choices in the rift between Baghdad and Irbil in oil sales solidified the latter's economic independence. The Turkish government has invested in the KRG oil fields, and at a cost to Baghdad, directly negotiated energy deals with the KRG. By establishing an escrow account in the Turkish state-owned Halkbank to divide the revenues of all Iraqi oil exports between Baghdad and Irbil, Turkey has provided the KRG direct access to its oil profits without going through the central government. The report concludes that Turkey's energy policies in Iraq provided Ankara a position of strength in Iraqi domestic policy, but it also helped the further decentralization of the state.

In this sense, an independent Kurdistan may take away Turkey's almost absolute control over these oil sales. Bayan Sami Abdul Rahman, the KRG representative in the U.S., told a group of journalists on Monday that if independence goes smoothly, Kurdistan could sign an economic pact with Baghdad. Kurdistan can also negotiate to pump its oil through the southern pipeline, which Turkey has no control over. Surely, Iran would also recognize Kurdistan, and at least in theory, ship Kurdish oil to the international markets.

Another concern for Turkey could be a change of leadership in future Kurdistan. Although Ankara gets along with Barzani's Kurdistan Democratic Party (KDP), it is not very clear if this tight relationship would continue in the case of any Goran or Patriotic Union of Kurdistan (PUK) governments. Both of them have positive views of the PKK, and also have strong ties to Iran. In an independent state, they would have more leeway to counter Turkish policies.

As a bright spot, there is at least one thing that can satisfy Turkey. Abdul-Rahman, the KRG representative in the U.S., said they would not unilaterally declare Kurdistan's independence. "The referendum, if it passes, would give a mandate to the government. We don't want to declare anything unilaterally. We want a dialogue with Baghdad. A negotiated settlement," she said. She also called on Turkey to focus on the potential benefits that can stem from an independent, robust ally in the future.

Still, I can't stop myself from thinking about the stark change in Turkish policy. Fifteen years ago, there was a Turkish state that would have gone to war against the KRG if they had wanted to seek independence. Now, the Turkish government only prefers to criticize such a bold move, underlying the interdependency between Irbil and Ankara.