We live in a pluralistic society. That means that no ideology dominates the others ... at least, that's the ideal.
First of all, it's interesting to see how the word "ideology" is no longer connected with an ideal. An ideal is acceptable and worth pursuing. An ideal is something that we should all strive towards. An ideal is encouraged. However, an ideology is not. That is, a structured set of propositions that are centred around an ideal is far from encouraged, and a way of life to accompany those propositions is even more discouraged. Therefore, under pluralism, it is acceptable to have an ideal, as long as you don't do anything to make that ideal a reality.
Secondly, the very idea of avoiding domination by a single ideology is in itself an ideology. If a person steps out of line by suggesting that any particular ideology should be either promoted or opposed, that person is either an ideologue (dangerous in the extreme) or just plain intolerant (to be re-educated).
Within pluralism is the inherent contradiction that pluralism itself is something that seeks to dominate everything else. I suspect that there are only two ways for it to function. It must either be a pluralism that encouraged ideals that are never acted upon, or it must be have a mechanism to prevent any particular ideology from actually gaining power. Perhaps the tendency for contemporary democracies to elect centrist governments is the actualisation of this second condition. Extremist governments aren't elected for long. They either get voted out or pervert the electoral process to ensure that they return.
The sustainability of a pluralist society relies on people rejecting the actions of their own ideals.