Both parties are total sellouts to their REAL constituency, which happens to be who has the money they use to run for office on.
Neither has principles-- excepting of course, the financial kind already stated.
The modern world treats election campaign funding as a kind of investment. That is why
Chris Dodd had that faux-pas where he alluded to quid pro quo not that long ago (which he backpedaled on hard afterward.)
Many of the more democratic bent like the idea of a singular power base, (like the federal govt) because it allows them to force social issues through with a hot iron poker, and tell the rest of the country to suck it up. I am against this view, because it also permits the same mechanism to be used for far more diabolical changes by corrupt interests. I consider the crude antics and pugnacious behaviors of the various state legislatures against things like abortion and gay marriage to be a lamentable, but unfortunately necessary concession against that very dangerous prospect. Much like allowing free speech requires that you allow people to say naughty things.
Being one of these mythical centrists, I am naturally unpopular by the standards of both prevailing camps. The neocons are too corrupt by big business interests, and the liberal dems are too corrupt with their tyrannical approaches to social reform, and beholden-ness to big media. The neocons find me and my views to be far too liberal. The liberal dems find me offensively conservative.
I actually would prefer that our government be constantly deadlocked, constantly stonewalling itself, and in general, ruled at the state level rather than the fed, because it would effectively stonewall things like FISA, the US Patriot act (and subsequent "Freedom" act), and things of that nature. Actual separation of powers helps to cement this deadlocking. I am very much against the flagrant abuse of the commerce clause to authorize "anything the fed wants."
Currently, BOTH ideologue groups have been eroding the separation of powers, because that separation obstructs furtherance of their goals. (Fast-track powers of the POTUS will enable end-runs on congressional power under the auspices of "trade agreements", and consolidated power bases with strong executive order capabilities will enable liberal dems to make executive proclamations to get the social changes they want, no matter how unpopular they are in the general public.) That is why both groups are equally supportive of things that are actually eroding actual freedoms of the US populace. (things like the Freedom Act, et al.)
I am actually quite disgusted with the dregs that have been scrapped up from the barrel for this primary season. They have turned the US presidential election process into a genuine dog and pony show.