This is a fairly interesting report from the Counter-Extremism Project which provides a generally accurate view of the “far-left” in the US. Read the report here. As a caveat, the Counter Extremism Project is a systemist group associated with former high-ranking government officials. Their objective is to legitimize the mainstream system while opposing its enemies in the same way that the Southern Poverty Law Center and Anti-Defamation League represent the liberal wing of the ruling class, the Center for Strategic and International Studies represents the national security establishment, and the groups around David Horowitz represent the right-wing of the ruling class.
As a general rule, I consider the Left, Right, and Center to be the “enemy” for the most part. The Center is the most immediate enemy because it’s actually in power. However, there are clearly enemies on the far left (e.g. totalitarian Marxists) and far-right (e.g. actual fascists and Nazis). Given the ongoing fragmentation of US society into warring tribes, the best option is to work to strengthen anti-authoritarian, anti-statism, decentralist, libertarian, or anarchist tendencies everywhere on the political and cultural spectrum, while resisting the influence of the ruling class Center as well as the most dangerous sectors of the far-left and far-right. See my concept of the 0 to 100 Scale. Unfortunately, most anarchists are worthless on this question because they’re only interested in upholding their preferred cultural paradigm, which is even more problematic given that it’s basically an exaggerated version of the dominant ruling class paradigm.
The best position for anarchists to take at present is to recognize that different political ideologies are not different from religions, each with their own dogma, mythical narratives, tribal morality, superstitions, rituals, taboos, and icons. Whether one thinks any of their respective theologies is “true” or not is irrelevant from a practical perspective. What we need to be thinking about is how anarchists would have approached situations like the Thirty Years War, the English Civil War, or the Lebanese/Syrian civil wars pitting countless numbers of sectarian groups and constantly shifting alliances against one another. The USA can still sink a long way before it reaches the level of violence found in many parliamentary states like those in Latin America, Africa, and South Asia, much collapse into total civil war. But increasingly were are moving toward a “cold war” version of the multi-faction sectarian religious wars that have been found in other societies, past and present.