Iraqi Kurdistan Regional Government (KRG) leader Masoud Barzani's determination to hold the independence referendum in northern Iraq has sparked additional turmoil in the Middle East. While the governments of Turkey, Iraq and Iran strongly protested the decision, Israel has voiced support for the move. Those countries that condemn the vote fear that Iraq's eventual dismemberment will provoke an instability wave across the region. This doesn't mean Iraq's disintegration will necessarily cause Turkey or Iran's collapse as well; for example, the former Czechoslovakia's dismemberment didn't provoke the same in neighboring Hungary back in the 1990s.
The main problem and the essential reason why Iran and Turkey are that worried is because they know the entire referendum process had been crafted elsewhere and not solely in northern Iraq. In other words, Iraqi Kurdish leaders couldn't have imagined organizing the referendum if they hadn't been encouraged by foreign players to do it. The latter are eventually "big" players upon which regional powers like Turkey and Iran have limited effect. Moreover, in the Middle East, we lack a regional integration project like the European Union, so no one can foretell where this dismemberment will lead.
That's why it is not difficult to see why Iran or Turkey are worried. It is also understandable why Israel is so pleased: It traditionally supports every move that will weaken an Arab state, and especially the Baghdad government that has close relations with Tehran.
As for the U.S. and Russia, officially, they oppose the referendum. It is not sure, however, whether they are opposed to independence or just to the timing of the referendum. We know, by experience, that the U.S.'s current criticism can perfectly disappear in a while, and Washington may work with the new independent entity without any problem. The same is also true for Russia. Maybe the reason why Russia is against the referendum is that they feel an independent northern Iraq will become a U.S. partner. However, it is also possible that in the wake of eventual independence, the rulers of the new entity may change and pro-Russian cadres may seize power. It happened many times in the Middle East before, and the Russians are particularly able nowadays in reversing situations that are not in their favor.
Despite the clear positions of regional powers and of the two great powers, we are not sure what exactly the EU thinks about the referendum. France and the U.K. have criticized it, but using a very mild tone. They don't want to anger the Kurds, of course, but they can't openly support an independence referendum right now either, as another EU member, namely Spain, too, is trying to deal with an independence referendum these days.
They can't probably say yes to one referendum while saying no to the other, even though Europe generally acts according to its immediate interests and not principles.
Moreover, Germany's position is not clear either, and that's one of the reasons why the EU can't make a decision about the northern Iraqi referendum. On the one hand, Germany has been pushed out of the Middle East, partly thanks to Turkey, and on the other, the country now has its own problems, like forming a coalition government in the wake of general elections and finding a way to save the EU's future.
Therefore, it is obvious that it is the two great powers that will decide what comes next in northern Iraq, and no one else. Every other development in the region, i.e. Iran's missile tests, weapon transfers to the PKK-affiliated Democratic Union Party (PYD), or the fight against Daesh are all related to these powers' bargains over the region's future. The point is, none of them really care about the well-being of the Kurdish people, but only about whom they can use for their own interests.