This is one of the smaller POD's, internationally speaking, it's entirely plausible and wouldn't hurt Mexico much. They might have never been invaded by the French, given the USA would presumably have paid more, leaving a better financial situation. US side of things, well, if it's an independent state, it's another left leaning Pacific state, probably more marginal elections go blue (or whatever TTL). If not, it is a part of massive union dominating behemoth California. Which is a good thing.
Why would the politics of Baja CA be similar to CA?
Also, if we have a large butterfly net, and assume the rest of history proceeds recognizably, Hollywood might not develop as the center of the film industry, depending on how much further away this pushes the border, exactly.