Freedom to speak your mind was guaranteed by the First Amendment to the Constitution along with freedom to assemble, to publish, and to practice (or not) the religion of your choice. The freedoms enumerated in the amendment serve one singular purpose: to prevent those in power from stifling opposition. Note that the amendment doesn’t say you can say anything you want to anyone you want, it says the government can’t pass any laws preventing you from doing so, which isn’t the same thing.
The authors of the amendment weren’t worried about your opinions, they were trying to ensure that those opinions would have a free marketplace of ideas in which to live or die.
Once upon a technological time, social media gave promise of being exactly such a marketplace. No gate-keepers! Except the savior had muddy feet in the form of algorithms that behaved exactly like gate-keepers to serve the purposes of the social media moguls that pander to the mob. The flood of garbage drowns out legitimate discourse because garbage is what draws eyeballs and prompts clicks.
There is a difference between false claims and true ones; fraudulent speech and virtuous protest. But who is to say which is which? The mob and the government (including the judiciary) have vested interests in the decision, which is where the free marketplace of ideas comes to the forefront.
In a free marketplace of ideas, you can say whatever you want, but I don’t have to buy it—I don’t have to believe you. Nor can you prevent me from hearing from your competition. As long as the marketplace of ideas is free—open to anyone who wants to use it—I can make informed decisions based on what I hear. It’s when voices are muzzled by the state, by the mob, by the algorithms and censorship of social media corporations, that I can’t hear them and my decisions become ill-informed and potentially wrong.
To cite an example, what if Donald Trump’s insurrection had succeeded four years ago? What if Mike Pence had tucked his conscience behind his sphincter where it had been hidden the previous four years and declared, despite his lack of legal ability to do so, that the electoral votes in Arizona, Georgia, and Wisconsin should go to Donald Trump? That would have tied the election in the electoral college and Congress would have made the final choice using the nonsensical one-state-one-vote procedure. Wyoming, North Dakota, Idaho, and Arkansas would outvote New York, California, and Illinois and “elect” Donald Trump.
The Supreme Court would surely nullify such malarky—or would it? Its own legitimacy is questionable after the way Mitch McConnell chose the last two justices, so what if the six-to-three majority approved the charade? Would you be free to speak against it? To shout from the rooftops and across the X-verse that the election was a fraud? That patriotic Americans should rise up and overturn the sham results? What other recourse would you have?
The real question is “could you?” If Mark Zuckerberg opens the floodgates of garbage to drown your Facebook posts, if police pepper spray your followers in the park, if the President declares from his bully pulpit that the only real news is the drivel that spills from his X feed, you don’t effectively have freedom of speech. You can talk—maybe—but you can’t reach an audience. Your ideas are dead before they ever reach the marketplace because there is no marketplace, only a company store where the shelves are stocked with propaganda.