The fact some individuals eventually pull their head out of their ass does not compensate for the damage caused by the many leftists that keep their cranium firmly embedded in their rectum. That aside, there is a wide gulf between simply having an opinion and endorsing an ideology that is destructive by advocating for its adoption in word or print.
As soon as you are willing to sacrifice the rights of one individual for the good of the many, you have become a collectivist and a Marxist.
That aside, the 1A would be wiped out by leftists.
If it was so easy, it would have already been done long ago. They have been openly expressing their hostility to the 1A for generations. Now the "enlightened" neocon/alt-right has joined them in opposing the 1A, the only difference is that they pinky-promise to only gag leftists.
They like it when it can be used to undermine their enemies and dispense with it when it can be used to destroy their enemies.
Which is exactly what you are proposing, just in reverse.
The 1A, like the entire Bill of Rights, is best when applied to a population bonded together by a shared set of ideals.
This is just collectivism. "Greater good"...
Leftists do not share those ideals and are entirely incompatible with the epistemology that generated them. Tolerating something diametrically opposed to your values is not a virtue.
Not just tolerating, but showing hospitality and love. We must love our
enemies. Yes, there is such a thing as using self-defense against a crook, but self-defense is only justifiable for operational threats. Just because you hate me doesn't justify me to nuke you. It's not until you make an actual move against me that I would (possibly) be justified. The law of Christ is a much higher standard and if we're serious about changing things, that's the only way it's going to happen.
wait for a leftist to do something overt before excising the cancer they represent is precisely why their systematic subversion is so wildly successful.
No, the reason it's so successful is that many on the right are
lazy thinkers and so they don't want to do the heavy-lifting of actually understanding, in detail, what is wrong with Leftist views. Yes, it's a pain-in-the-ass to have to refute them, but it is ground that must be tilled. Just covering the hard-pack and torching weeds is the lazy man's way out of proper tilling.
Understand what is wrong with Leftism, and how to refute it, and then you realize why it's not necessary to gag them. The more they speak, the more they just make fools of themselves; that is, unless their opponents are a bunch of lame-brain right-wingers who would rather drop JDAMs in the desert than actually be bothered to read a book.
Leftists do not do anything overt until after they have thoroughly subverted the existing institutions that would punish them for their actions.
The act of subversion itself is actionable. Teaching children Marxism in class is not a neutral 1A activity. And so on up the chain of causality. If a college professor at a private university wants to believe and teach whatever nonsense, so be it. He shouldn't be able to work on the public dime if he's teaching Marxism. And the moment he sits on a board or joins a political caucus, his opinions are no longer 1A abstractions, they are concrete and actionable. That
is putting the hand on the levers of power.