> ... in game theory when the other side always defects.

Consider the conservative position, and what strategy would work for conserving what is important to them. Any sort of compromise is a long term losing strategy, so of course they'll block progressive moves if they're capable. I'm not aware of any real trade ever being offered, something like: we want full on no joke equality of outcome for every flavor of the rainbow, and in exchange we'll give you the abolition of federal income tax.

Imagine if someone demanded you eat a sandwich made of human waste, and then they got upset when you refused to compromise and only eat half of it.