They don't need to persuade a majority of their fellow citizens, only a majority of relevant legislators.
Yep. The left is controlled by a loud mouth minority of people who are rabid, and quite insane, in their belief system and in their determination to force their will onto a rather apathetic populous. They control the media, big tech, education and for the most part DC.
Don't kid yourself people: the left is communist/socialist at their core, and that means they are atheists, and evolutionists. Essentially, they want population control so they are adamantly pro-abortion and pro euthanasia. They absolutely want a one-world government to control everybody, all the time. And, with big tech helping them out, they will get absolute control. Sooner or later, it's coming.
It's only because of people like you and me that they haven't gotten everything they want as of right now. But don't kid yourself, they want total and absolute gun control. The "progressive" left does not care about your well being, or your health or your religion, or your personal happiness or anything like that. They want total control. Absolute control. They think they know everything, and they think they are smarter than you and me.
And that's just the hard cold facts of where we are at in this USA, at this time. The Democrats should be renamed the Communist/Socialist Party of the United States. They are that far gone. The Rhinos in the Republican party are just mouth pieces, they really don't care either. They are, at best, apathetic to the plight of this country, and at worst, a Democrat underneath.