First, I’m sure it’s hard to imagine, but California could lose said showdown and find themselves obstructed from protecting even only California. Second, it’s not just some lone politician that would care. The whole Roe v. Wade thing should have made clear that half of the country had been seething to overturn it for decades. Our whole system is built on consent of the governed; Federal mandate is therefore tricky if one large state is in overwhelming support of an issue while another is overwhelmingly opposed.