[vkou]

So, the best case outcome is a less-democratic version of status quo (just like how California unilaterally drives ~all automotive regulations in the country, with nobody else having any input on them, despite every state having the 'freedom' to make their own), and the worst-case is a complete collapse of the common market.

Is that really what you want? It sounds absolutely mad to me. Your ideology is driving you to ask for a monkey's paw.

[eru]

https://en.wikipedia.org/wiki/Comparison_of_MUTCD-influenced... shows that different states in the US have slightly different road traffic signs.

And yes, voluntarily following an example is better than being forced to follow an example. Duh.

[vkou]

I'm not talking about road signs, which is completely irrelevant to problems common markets solve, I'm talking about how California can unilaterally apply its emissions regulations to the whole country, by virtue of being the largest, and most discriminating market in it.

Other states get the choice between not having cars, and following California's rules, despite having no input into them. Because it's uneconomical for manufacturers to produce custom, per-state models.

You're still forced to follow the rules, except that in the case of federal rules, you have democratic input into them, because you elect both the federal legislature and the executive.

In the case of non-federal rules, the largest state will set the rules for you, and you won't have any say in it (at least, if you want to have things like cars and drugs). That's not a choice.

Or, you could always take a look at how abortion rights are currently handled. Texas is suing people who get abortions in Colorado. Truly magical stuff. I'm sure the people in Colorado 'volunteered' for that.