The dialectic of base and superstructure are useful here. Individual politicians are real people. Often they’re cynics, sometimes cold and unempathetic, and sometimes true believers in various ways. Despite carrying out the wishes of capital, they’re not all meeting up in a room with porky to come up with a game plan. Instead, their actions are dictated by the many tendrils of capital embedded in our society. Campaign contributions and nepotism and bribery are all obvious things, but these things are also pressures from capital in imperialist countries:

• The content of the education system.

• The focus and bent of media outlets.

• The intelligence state, how it funds itself, what it views as national security.

• The threat to stability inherent to capitalism.

• The whims of the fed.

• The self-interest in imperialism.

• Lobbying efforts premised on local support, like keeping a factory open.

Anyways, I haven’t answered your question yet but the idea is that capital’s influence is everywhere but politicians are still operating at sn individual and party level as incoherent jerks and sometimes ideologues, all shaped by capital.

So what are they fighting over if it’s all just influenced by capital? There are two important systems operating simultaneously.

The first is that capital often has shared interests, but not always. Different industries or subsystems of capitalism will fight with each other, attempting to eat each other’s lunch. Finance capital wants to strip every retailer for parts, for example. Politicians, factions, and parties will align themselves more with one of these industries and fight on their behalf. Our good comrade Joe Biden was notoriously in bed with credit card companies early in his career - Delaware is a hotbed of finance capital. Under the dictatorship of the bourgeoisie, politicians and the state often hash out the contradictions of capitalism, including the anarchy of production and these fights among the bourgeois class.

The second is that because there is still much consensus among the bourgeois class (keep wages fairly low, keep unemployment high enough to ensure this, etc), this would leave too few issues over which to have a supposedly democratic exercise. Politicians lean heavily into “non-economic” issues in this vacuum. It’s not that all of the issues are invalid or brought forward in bad faith, just that the inherent framing under hegemonic capitalism seeks to remove these issues of their economic basis and basis of social control in favor of capital and instead make them into a culture war. This framing is promoted by the media, by academics paid to adopt particular modes of investigation, and by politicians themselves that seek to hash out issues based on their individual bourgeoisie morality rather than systems of oppression rooted in capitalism. This is how politicians distinguish themselves from one another. Many of them are true believers in the culture wars, including the most reactionary ghouls, but this is itself still a product of a capitalist society. There is little relation between the Bible + Jesus and the things that right wing Americans focus on politically. Jesus wasn’t obsessed with supporting a racialized scapegoating of issues of poverty. They’re carrying out a social function required by capital which is to divide the working class via marginalization. What they’re really responding to is a degradation in their conditions but the only way they know how to respond is through a false consciousness backed by factions of capital. The historical process of propaganda bears this out, like the invention of blackness and the consistent dehumanization of the imperialized.

So, short version: politicians are fighting in their own interests, expressing the contradictions of capitalism. Sometimes it’s fights among capitalists and sometimes it’s over what is left by the vacuum of consensus, a bourgeois social critique. They really are attempting to secure their own power, which is why they seek out the money and influence and media attention and to disenfranchise. It just operates under a system for by and of the interests of capital.