Party A lies to X supporters in order to get power.

Party B lies to Y supporters in order to get power.

Neither party gives up meaningful government power at the benefit of the citizen.

Both have their "party line" (lies) that they drone out.

This doesn't mean that either side doesn't have well-intentioned people rising up within the party that truly want to make a difference, but they eventually get ground down into being yes-men/women to the party or weirdo outcasts like Rand/Ron Paul who are the party punching bag.