I think thats a 'dont know' then on how California would stand if it became independent.
Turkeys membership is stuck until they can accept normal rules of judicial process and freedom of the individual. The eu had decided it could put up with impoverished members but not ones with different ideas about freedom.
There's no movement a foot for CA to leave the Union, it's been an integrated part of the US for 161 years. It's not really comparable to Greece, or the EU in any way save we are 20% over budget, but we were this far underwater in '02, and muddled through the next 6 years. We are in need, as is almost all of the Western world, of structural fiscal reforms that limit spending to a fixed percentage of State, or Federal GDP. In truth, the UK's finances are probably the most similar to Greece's. Fortunately you are not in the euro.
Though you hear it mentioned often, even over here, I can't see how it would be practical for either Scotland or Wales to leave the UK. The one place where you do hear secession talk here is Hawai'i, which has only been part of the US for 50 years, and is remote geographically. Although politically intriguing for anyone who is part native Hawai'ian, it's impractical economically. Perhaps they will increase the "homelands" for native Hawai'ians because of it. It may not hurt that our Pres. is from there.
Pushing Turkey away from the EU has given considerable fuel to the reactionary Islamic movement there who are on the verge of ousting the old guard CHP. They have been in power, along with the military, since the '20s. If one is rebuked, while at the altar, why not find another union where you are welcomed? Having spent some time in both Turkey and Greece, there is no question in my mind the Greeks overplay the fear of a Turkish invasion. My guess is so long as Cyprus remains an unresolved issue, both nations will feel like they are in some form of the Cold War, and misappropriate defense resources.
To be sure much of what is now Turkey was once Greece, Istanbul and virtually all of the western coast, but geographically speaking it makes more practical geographic sense for that region to be tied to the continent than to Greece. As to the Haga Sofia being more Greek than Turkish, I don't know. It's a world heritage site, which has been in Turkish hands since 1200 when it virtually abandoned by the Greek Orthodox Church. It continues to be a place of religious, historical, and cultural significance for anyone who is part of any branch of the Orthodox Churches. The Turks respect this. Besides they have the impressive Blue Mosque across the square to worship in.
Pushing Turkey towards Islam by rejecting their even conditional entry into the EU probably did Turkey an economic favor, but it also offended a long time democratic Islamic ally to the West, perhaps the only true one, in the process. Turkish law can be harsh, ask any Kurd, but there have been considerable reforms made to the justice system in the last 30 years.