Not OP, but dialectics not dialects. Here's how I interpret it:

The phrase dialectics of power is framing the concept that a lot of a political discourse is centered around arguments of who has power, and who doesn't.

Its superficial arguing. "Oh no, X has won the house that means the future of Y is in peril!" instead of discussion around why X won the house or why idea Y is something we want in our future.

Much of this line of thinking is about making sweeping assumptions about policies, and what groups of people/political organizations believe and support.

Talking in the context of power relations seems inherently combative a form of discourse. If you feel you're up against someone with a differing viewpoint on a topic and it's so because of their different power vantage, you are going to what: either fight argumentatively or lecture to the person in front of you that they're naughty and need to see it. It doesn't seem productive.

As it plays out in the US, the discussions are framed in terms of two-sided issues, where the only real option is to choose one of those sides: Republican vs. Democrat, Capitalism vs. Socialism, Pro-Vax vs. Anti-Vax, etc.

It's almost taboo to suggest that these enforced dichotomies aren't really helping anyone but that they do seem remarkably well-suited to preserving the status quo.