Political terminology in the United States is MASSIVELY warped by entities who spend literally millions of dollars in an effort to connotatively redefine words. When you (re)define words like "conservative" or "liberal" you risk alienating people who have been conditioned to have an emotional response to either definition. If you define a term in a way that seems pejorative to your reader, the reader will weight every subsequent statement against the rigor they think you brought (or did not bring) to those definitions. Your essay will entirely fail to persuade if it rests on (perceived) faulty definitions.
When writing to a largely US audience, no attempt at honest communication will be aided by the application of political labels.
Here's a test: can the essay be rewritten without that political terminology? Reader "nirvana" used the terms "cowboy" and "architect" to describe his two axes. ( http://news.ycombinator.com/item?id=4367328 ) I very much prefer those terms. Yes, they're also connotative and subjective, but as analogies they map much better onto the subject being discussed.