The UN is generally loath to recognize break away states. And the US has that whole security council thing allowing them to unilaterally nuke recognition. So the recognition of any break away US state is largely contingent of the US leaving the UN. Recognition of your new nation by other nations. Through the UN or individually is neccisary for things like foreign aid, loans, military or diplomatic support. Things you generally need even to get to independence. This exact dynamic has crippled more than a few new nations/revolutionary attempts. Including the CSA.
California’s closest trade partners are the rest of the US. Trade partners they will likely be cut off from unless the process is amenable and peaceful, which I think is incredibly unlikely.
None the less similar road blocks to continuing trade and relations with Asian countries as is, exist. And a new nation essentially discarding access to one of the largest markets in the world, is going to find itself with a suddenly shrunken economy. To say nothing of what this all means for whatever currency they launch. Even with strong production and trade deals. If your new currency flops you’ve got a cratered ecconomy.
None of this is to say any of these things are insurmountable. Simply that it is in no way as simple and immediate as popping out a wholly formed, as is, functioning nation. Recent history has very few examples of new countries that don’t go through significant periods of instability and economic turmoil. Most go through a long period where inherent inequality is the order of the day. Off the top of my head, the countries that best avoided that were countries leaving the UK but staying in the common wealth. And the Axis nations under occupation after WWII. In those cases you’re talking about a new state, or new government being heavily propped up by a significantly richer, more stable outside state (or multiple outside states). Who will prop up an American State that breaks off from the US? The US is very unlikely to do so. As are the EU as a block. The UK did Brexit, but that’s likely to have serious impacts on their stability and wealth. So Russia and China. Which sounds like an awesome pathway to a progressive utopia!
