The history of politics is relevant, yes, but sources of historical events tend to be biased somewhat, too. It's also the case that parties do tend to act differently in the face of historical context. Take Labour in the 60s and in the 90s. Basically different entities all together. I'm not talking about a full and complete understanding of politics, just a basic awareness of what the parties at least want you to think they stand for. If you do read them, it's not like all the parties are saying exactly the same things so they do provide some basis for differentiation if nothing else.