"The word 'ideologue' is a technical term within political science but an insult within American politics. There is nothing wrong with approaching politics ideologically — and that's particularly true when you compare it to the major alternatives, which are approaching it transactionally or as a pure partisan."
David Roberts continues:
So perhaps a simpler way of putting the conclusion is that the Republican Party is motivated by a general philosophy while Democrats are motivated by specific policies they want to achieve.
From the article, quoting Ezra Klein:
David Roberts continues: