California has access to all the West Coast trade-ports between the US and China. With these ports in place, we don't need to rust-belt states to ship-in goods. An our economy is centered information technology and entertainment, so we don't really need to worry about reduction of economically viable exported goods (all farmed and manufactured products will be consumed internally, thus bolstering that aspect of the California economy).
Commerce isn't as simple as importing and exporting physical goods. Broad sanctions could, for example, prevent American companies from spending money on ads with Google, or American engineers from moving to California to work for them.
