Ask Lemmygrad

You should reframe this question looking at it with a more materialist perspective. You cannot analyze something like this in a vacuum without context. The point at which critical support is or is not justifiable depends on the circumstances.

Critical support is not about some sort of net moral value that you assign to someone, like counting up the good and subtracting the bad from it and seeing if that is above or below some critical threshold for support. That sort of moral arithmetic is un-Marxist and not dialectical.

Critical support is about the function that something serves in the broader context of a given struggle. It is about understanding and identifying primary and secondary contradictions.

But the bigger problem with this question is that it's sort of a moot point, because if a regime is that reactionary and fascistic that it has zero redeemable elements, then, in the post-WW2 world of unipolar imperial hegemony that we live in, it will be aligned with western imperialism and not against it.

Western imperialism has always and continues to deliberately cultivate and seek out the most reactionary elements in any society to prop up. Whether as open allies as they did with the military dictatorships during the cold war, or whether it is with neo-fascist, sectarian and terrorist proxies like they are currently doing in Ukraine, Syria, and so many other places around the world.

Capitalism and imperialism require reactionary regimes in the periphery to divide, oppress and crush colonized populations, even as they pretend and put on the liberal mask (as they have needed to do since the October Revolution) at home in the imperial core. This is not a moral choice, it is an inevitable consequence of the material requirements of global imperialist exploitation and extraction of super-profits.

Even in the case of former imperialist proxies and puppets which have outlived their purpose and which the empire has decided to ditch, such as Saddam Hussein, the question isn't "how intrinsically bad are they?" it's "what is their current function in the global system of imperialism?".

A regime can remain exactly the same but if the circumstances change then so might a materialist assessment of their role in the broader global context. Should communists have supported Saddam's regime when he waged war against Iran on behalf of the US? No. Should communists have opposed the US sanctions and eventual regime change war against Iraq? Yes.

Why? Clearly his regime didn't become any less reactionary from one decade to the next. But its position in the world imperialist system fundamentally changed!

On the flip side you have Al Qaeda, also a creation of the empire, also a proxy which the US eventually turned against...at least formally. Should communists support them? Obviously not.

Not just because of who they are but because even though they claim to oppose the US and the US claims to oppose them, they still fundamentally serve to further the goals of US imperialism and Zionism in West Asia, as we have seen painfully in Syria.

The answer to your question therefore depends on context and there is no blanket answer that can be given since each situation requires its own proper analysis. And not just in relation to US imperialism, which is only one facet, but in relation to the broader goals of the progressive and communist movement.

Does a regime or faction help or hinder those goals? And how do local and global goals align or conflict with each other? What is the biggest obstacle to progress? What is the primary contradiction and what is secondary?

As you can see this gets quite complex and it is best to approach things on a case by case basis. Even then communists will sometimes disagree with each other on the answers to these questions.