You mean like the SCOTUS has done in literally every first amendment case brought before them for the entire history of our country? Seems to have worked pretty well so far. I get ya though, scary government boogeyman and all.
Sort of.
But SCOTUS has, quite correctly, erred on the side of free speech whenever possible. There are lots of cases and precedents and such, but I think what it comes down to right now is that the attempt to stifle the speech has to pass the strict scrutiny test, which is that there is a compelling interest to stifle the speech, that the action of stifling the speech serves that compelling interest, and that no lesser action is available that would also serve that compelling interest.
I think you would have real difficulty arguing before SCOTUS about Alex Jones on points 2 and 3.
When it comes to point 1, even the existence of a "compelling interest" might be difficult. Obviously, safety of citizenry is a compelling interest, but not in general terms. You would have to establish that the speech being stifled actually posed a threat to the safety of the citizenry. That's where the "clear and present danger" test comes in.
Technically, that, specific, test, is not in current Supreme Court precedent, I believe, but I don't know if there is anything specific that took its place. I know that you would have to do better than "Somebody hearing that might decide to perform a violent act." If there is a specific incitement to violence, you could get past the first leg of the strict scrutiny test, but simply a provocative statement that might get someone so mad that they might take it on themselves to commit violence isn't going to cut it.
And, I might add, that's a good thing.
Now change the "something" to "shooting up a pizza parlor", and "causing death threats on the lives of the families of slaughtered children" and the "someday" to, "it's already happened in the past", and we seem to be getting somewhere.
So, if I rail against Mexicans, someone might shoot up a pizza parlor? And if it happened in the past, it can't be "present" now can it?
In the actual, specific, case of Pizzagate, there might be a case, because it involved specific allegations about specific people, and created a false sense of belief that there was imminent danger that would justify violent action. I think a case can be made there.
In the general case, you are dealing with possible chains of events that someone might do something, possibly something similar to what someone else did in the past when some different person said something analogous. I think you would have to be able to make a specific link, and that would be hard to get past the strict scrutiny test. And, once again, that's good. It ought to be difficult to restrict speech. The burden of proof ought to be on the one who wishes to restrict the speech.
As for "caused death threats" in other cases, that's not enough. There were death threats to the Covington Catholic kids after false statements were published about them in WaPo and NYT. Should we throw the editors in jail? I'm sure Mr. Trump would be happy to oblige, and that's the point.