If the first amendment didn't exist the government could force a bakery to bake Nazi cakes. They can still force you to bake cakes based upon certain protected classes. So I guess if political affiliation became a protected class then maybe the government could force a bakery to bake a Nazi cake? I dunno.
> So if all the banks decided to stop doing business with all Democrats, you'd argue that was protected by the First Amendment?
Correct, it is. It would be foolish business, but they could do it. At least, that's my understanding.
What would more likely happen is this:
> Business announces no-Democrat policy
> Policy goes viral
> Business cancels policy due to public pressure and other businesses cutting ties due to the bad PR
> Republicans yell about 'cancel culture'
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> So if you own a bakery and a Nazi insists you bake them a Nazi cake, you have to bake it I guess?
The first amendment literally works the opposite of this. That's exactly the kind of thing a business can refuse (though in some cases there are narrow carve-outs for certain types of identity).