The only reason you think it is nonsense is because it shows the stupidity of your position. It's why you refuse to answer and instead are trying your hardest to deflect.
It is rather obvious that you are the boy that needs to do some more thinking.
I can't believe I have to spell this out for you. You asked:
"So in your mind if the people of California decide to join Russia then it is then OK for Russia to bring over troops and annex the state. The federal gov should not get involved."
On a personal note, I'd love nothing more than to see California secede -- and then put up a wall. LOL
On a realistic note -- California has never been associated in any way with Russia, whereas the Crimea was once a part of the same union as Russia - the Soviet Union. Extended families live in both of those nations, but not so between California and Russia. That's why your question is nonsensical. It has nothing in common with the Russia/Crimea situation.
If, however, California elected a governor and the President of the US paid someone to run that governor out of tow and propped up a new governor that was unfriendly to Californians, we very well might see California try to secede, and, if the US govt. sent troops into California to keep the natives in line, Mexico (if it was stronger than it now is) might decide to protect the Californians from the US Govt. And, because a high percentage of Californians are from Mexico, perhaps they'd vote to join Mexico.
But, that's unlikely due to the strength and integrity of the parties involved.
If Mexico did that, based on the attacks of the US Govt., I'd say they were justified, just as Russia was justified to go in and protect the Crimeans from the Ukrainian rogue govt.
If Russia tried to annex California, however, I would not support it, as bad as I'd like to see California be a part of a different nation. I could not support it because Russia has no territorial interest in California. Not now and not in the past.
Now, can you see the silliness of your question?
Hopefully so, because I don't have any Crayons handy to spell it out in big colorful letters for you.