One thing everyone on here should agree on is if we want to get anything done, we need more people on our side. That's true regardless of what you want to do or who you consider to be on our side.

This post is an effort to start a more focused discussion about who is already on our side and how to bring more people in. The obvious danger is watering down leftist movements with unprincipled libs, but that's why a pipeline strategy is so important. It's not inviting a bunch of libs into the lefty clubhouse as-is; it's giving libs (and other groups) the tools to keep taking that next step in the right direction. It's not "everyone needs to 100% agree with me or I refuse to work with them in any capacity;" it's getting people started down the right path and then making it easy for them to keep going.

Who is already on our side? Who is "the left"?

You will sometimes hear takes in the form of "this person who describes themselves as a socialist, who does praxis of some kind, and who is more critical of capital than 95% of the U.S. population is actually a :LIB: -- I'm the One True Leftist and no one is as leftist as me." This type of take is counterproductive in the extreme. As the chuds in Michigan just showed, you're not starting a protracted people's war with a dozen of your buddies (and you're certainly not accomplishing any non-violent political action without broad public support). We need to grow our movement, and starting from the premise that the vast majority of the country (even extending to the vast majority of self-described leftists) is so liberal they should be treated with contempt is a failing strategy.

So who is "we"? Who should we consider to be "on the left"? I suggest the following definition:

If you are willing to seriously criticize capitalism, even some imaginary "pefected" capitalism, you are on the left. This means you should be treated with good faith and critically supported.

There is a real difference between those who will seriously criticize capitalism and those who will cheer it on despite dangling left-ish promises to get support. Note that excuses for capitalism ("that's just crony capitalism") or minor quibbles with capitalism ("yeah, landlords shouldn't be able to abuse tenants, but fundamentally there's nothing wrong with owning tons of property and renting it out") are not "serious" criticisms. That split between those who will seriously criticize capitalism and those who won't is where we should draw the line between who is broadly on our side and who isn't. The people on the left of that split have at least some theoretical understanding of the failings of capitalism and are at least willing to contemplate alternatives that go beyond "but what if we just did nicer capitalism?" We can and should criticize those people where appropriate, but we should (1) assume they are acting in good faith until there's concrete evidence to the contrary, and (2) support them (again, critically) because even if they aren't our preferred flavor of leftism, their success will help grow the left as a whole. To do anything less is a fast track to "I'm going to start a protracted people's war with a dozen of my True Leftist friends because I've alienated everyone else on the left" territory.

Who should the left appeal to? Who should be the targets of our pipeline?

The short answer: The left should appeal to everyone, because no one knows how to build socialism in the imperial core and we don't know with certainty who all might take the first steps towards leftism.

The long answer:

1. While we should appeal to everyone, we should put different levels of effort into different groups depending on how likely leftward movement seems. It's one thing if a left politician goes on Fox News, or if a left organization tries to reach out to chud territory -- it's another thing if that's the primary focus of your strategy at the expense of groups that are more likely to move left. The most effort should be directed at the most persuadable groups, even if leftist arguments should have a presence in spaces where very few people will fully adopt them.
2. We need different platforms to reach different groups. If you aren't into a certain left platform's style, that's OK (so long as they appeal to some other persuadable group, and so long as they aren't harming the left as a whole more than they're helping). We also need different platforms as experiments to determine the best overall pipeline strategy -- again, no one knows how to build socialism in the imperial core, so anyone out there trying to figure it out should at least be treated in good faith.

You mention different groups. What are these groups, and how should they be treated?

Attempting to develop precise definitions of every meaningful "group" in the country rapidly gets extremely complicated, to the point where its usefulness can easily decline. For our purposes, it's enough to talk about three groups of non-leftists that we should be appealing to:

1. People who won't even listen. These are people who will reflexively, unthinkingly defend capitalism and American imperialism and a whole host of other awful things this country does. Chuds, the Blue Lives Matter crowd, your hardcore Trump supporters, and other types of people who are broadly reactionary, and who are broadly moving towards fascism. We shouldn't waste too much time with these people, but we should not let their ideas go unchallenged and we should leave leftist breadcrumbs for members of this group that are not yet fully committed. Some of them will peel off, and others might be softened up/backed away from reactionary bloodlust -- think of how Bernie could move some of this crowd to "I'll never be a socialist, but at least that guy isn't your typical full-of-shit politician." Some libs are included in this group, too; see the "proud capitalist" wing of the Democratic Party. Mercilessly dunking on these people is better than OK, we should assume they're trolls or otherwise wasting your time, and we should never support any politicians or groups of this type even if they superficially appear to be doing something good.
2. People who will listen, but who will not move left soon. These are mostly libs and apolitical folks. When they are politically active, they at least see that Republicans are bad, although they don't fully understand why they're bad, the extent to which they're bad, the extent of the overlap between Democrats and Republicans, or how ineffectual Democrats are at either resisting Republicans or doing anything positive. The reason they won't move left anytime soon is they don't understand all these things, and it's our job to educate them. Yes, that falls to us; "it's not my job to educate you" will get us nowhere and get nothing done. We should be pointing out the contradictions in liberalism to this group, explaining leftist alternatives (this is crucial; otherwise we're just complaining), but otherwise keeping the theory pretty light. If you want to teach someone history, for instance, you don't start by throwing a grad school seminar reading list at them; you start with the basics and build from there. This is the crowd where a wide variety of left entry platforms is most useful. Some people will be most responsive to anti-war and anti-imperialist arguments, some people will be in the healthcare pls crowd, some people will enter through tenants' issues, some people will enter through living wage arguments, etc. Dunking on these people is OK to an extent -- tough love and good-natured teasing can be valuable for challenging deeply-held beliefs, but we don't want to cross over into alienating some of the people most likely to eventually move left. Humor, information, plenty of good-faith responses, and selective dunking is probably the best approach. Politicians and groups of this type should maybe be supported only if there is no meaningful left alternative.
3. People who will listen, agree, and change. These are mostly people who have grown tired of liberalism or apolitical folks who never bought into the Democratic Party in the first place. Here, it makes sense to get into theory beyond "here's why capitalism is bad and what a leftist alternative would look like." It's important not to get into destructive pissing matches with this crowd even if you disagree with them. They're either on our side (if they have come around to seriously criticizing capitalism) or rapidly approaching. That's a big step, and gloves-off shitting on them over vestigial liberal ideas can still derail their leftward movement. "If they get turned off at this stage they weren't a True Leftist to begin with" is nonsense, as of course they aren't already your idealized True Leftist -- the whole point is that it's a pipeline, which means there will be some people who haven't reached the end quite yet. These people should be treated as if they're already on the left: with good faith until there's a damn good reason to change that.

"But what about the groups Lenin, etc. identified?" History is often informative, but we have to walk the line between not repeating old mistakes and an un-scientific view of history as a set of near-prophetic laws that will never ever change no matter what context they're applied to. There is nothing more alienating to potential leftists than making a good-faith effort to move left and being met with "oh you're a Social Democrat (for example) so you're really a Social Fascist." Serious leftist aren't dogmatic; they're practical and recognize the need to bring people in.