People fail to realize that "CA" is NOT California. It's a federal region where taxpayers live. Did you EVER gotten mail from some gov't agency addressed to California, Texas, or Florida, etc.??? NOT A CHANCE!
And since I don't live in that federal region, I DON'T pay income tax, and IRS knows it, and doesn't even send me their tax demands.
ZIP codes are yet ANOTHER snare to pull you into federal and STATE jurisdiction. Just try to get an ID, Driver License or another gov't benefit WITHOUT ZIP code. It CAN'T be done, even though the USPS Domestic Manual says that ZIP codes are NOT required for First and Priority mail.
So for example Alabama or Ala. means a state of the Union, while AL is a CODE for a corporate subdivision of the federal gov't, ( the District of Columbia). That is, the federales regard all federal regions within Alabama, under the code "AL". And if you volunteer to be within such federal region, they will not argue with you, since that gives them jurisdiction to enforce federal laws over you.
In other words, "AL" is NOT an abbreviation of Alabama, a State of the Union.