Since ideologies amount to differing ways of defining the world – different accounts of what counts as a fact, as evidence, and as a sufficient definition — ideologies necessarily come into conflict not only in principle but especially in human behavior and interaction. Where ideologies are in accord, disagreement may be worked out in terms of commonly accepted and acknowledged principles of conflict resolution.
Two people committed, for example, to the guidance of formal logic, to empirical data (confirmed to a high degree of probability), and to a foundational set of axiomatic principles have a prospect of settling any disagreements that may arise between them. All such disagreements would be, by definition, a consequence of the incorrect application of logic, incorrect evaluation of data, or misapprehension of axioms. Likewise, two adherents to a particular subset of a particular religion would have greater chances of successful conflict resolution than members of two mutually exclusive faiths would have.
People whose most fundamental interpretive commitments are defined by conflicting assumptions about the nature of experience cannot, in principle, resolve the differences in a way that comports with the conflicting worldviews in question. Thus, pragmatism inclines people to deviate from consistency with their assumptions at least insofar as doing so makes coexistence and a degree of toleration possible. The negotiation of this compromise we call "politics".
Note that while practical matters force a negotiation of conflicting perspectives in terms of compromise, practical matters are not the only cause of compromise. Thus political compromise is interwoven with compromise that occurs for other reasons. For this reason, political thought and action are not reducible to an algorithm.
Politics always involves not merely negotiation but also discord. The discord provides impetus to the protection of ideological and presuppositional interests so that compromise does not lead to self-obliteration. The self-protective impetus of ideological aggression is captured well in remarks made by the seventeenth-century kensei Miyamoto Musashi:
When we are fighting with the enemy, even when it can be seen that we can win on the surface with the benefit of the Way, if his spirit is not extinguished, he may be beaten superficially yet undefeated in spirit deep inside. With this principle of 'penetrating the depths' we can destroy the enemy's spirit in its depths, demoralising him by quickly changing our spirit. This often occurs.
Musashi here calls attention to the notion that winning the battle and winning the war are two different and not necessarily concomitant things. Redrawing the geographic and political boundaries which define the dominion of ideologically opposed bodies of people is a compromise which is provisional at best. The impetus for self-definition provides also for other-negation, not necessarily in a violent mode, but always in a mode that removes the threat of self-negation. Miyamoto Musashi's comment is directed toward this idea. If one protagonist in a conflict successfully eradicates the ideological underpinnings of the opponent, the impetus for self-definition is sated, and the threat to self is abated.
It is perhaps most characteristic of politics that, although the goal of self-preservation motivates every negotiation, the rhetoric and intercourse of political participants is not necessarily a rhetoric of violence or conflict. Approchement, appeasement, aggiornamento, détente, sympathy, aggression — all of these terms can characterize political interactions which at their core have the goal not of compromise but of dominion. Says Musashi,
When you decide to attack, keep calm and dash in quickly, forestalling the enemy. Or you can advance seemingly strongly but with a reserved spirit, forestalling him with the reserve. Alternatively, advance with as strong a spirit as possible, and when you reach the enemy move with your feet a little quicker than normal, unsettling him and overwhelming him sharply. Or, with your spirit calm, attach with a feeling of constantly crushing the enemy, from first to last. The spirit is to win in the depths of the enemy. These are all ken no sen (to set him up).
~ same, p. 71.
For good or ill, commitment to a perception of truth always entails hegemony, and denial of truth is itself a commitment that entails hegemony. So, politics is always Kendo, the way of the sword, and ideology determines whether and in what way that sword is metaphorical.
(Note: this piece is from spring of 1994, when the intarwebs consisted of Usenet and Scott Yanoff's list, which was incredibly useful in tandem with Lynx in a world of gophers and Archie.)