As mentioned above, be very, very sure about what ethical framework you're working within before having a political discussion. A consequentialist and a virtue-ethicist will often take completely different policy positions on, say, healthcare, and have absolutely nothing to talk about with each-other. The consequentialist can point out the utilitarian gains of universal single-payer care, and the virtue-ethicist can point out the incentive structure of corporate-sponsored group plans for promoting hard work and loyalty to employers, but they are fundamentally talking past each-other.
Um, "hard work and loyalty to employers" can also be interpreted as desirable things that raise total utility in the long run. (Also note: the above is not at all an accurate description of any political position that I know off, I was just going with eli's example.)
This is a broad point in favor of consequentialism: a rational consequentialist always considers consequences, intended and unintended, or he fails at consequentialism. A deontologist or virtue-ethicist, on the other hand, has license from his own ethics algorithm to not care about unintended consequences at all, provided the rules get followed or the rules or rulers are virtuous.
Except, as I mentioned above in practice the conventionalist dismisses any consequences he can't or doesn't want to measure as "irrelevant virtue-ethical considerations". And that's not getting into his license to define the utility function however he sees fit.
Um, "hard work and loyalty to employers" can also be interpreted as desirable things that raise total utility in the long run.
Sure. But then you've already lapsed into consequentialism, and thus stuck yourself with a mandate to consider the trade-offs between desirable and undesirable consequences. This is not what deontological and virtue-theoretic politicians actually do. What they actually do is see an undesirable consequence, and start loudly pointing it out, signaling "Look how morally brave I am for being willing to let this sort of thing happen out of pure principle!"
-- Mark Friedenbach
Of course, with the prompting to state my own thoughts, I simply had to go and start typing them out. The following contains obvious traces of my own political leanings and philosophy (in short summary: if "Cthulhu only swims left", then I AM CTHULHU... at least until someone explains to me what a Great Old One is doing out of R'lyeh and in West Coast-flavored American politics), but those traces should be taken as evidence of what I believe rather than statements about it.
Because what I was actually trying to talk about, is rationality in politics. Because in fact, while it is hard, while it is spiders, all the normal techniques work on it. There is only one real Cardinal Sin of Attempting to be Rational in Politics, and it is the following argument, stated in generic form that I might capture it from the ether and bury it: "You only believe what you believe for political reasons!" It does not matter if those "reasons" are signaling, privilege, hegemony, or having an invisible devil on your shoulder whispering into your bloody ear: to impugn someone else's epistemology entirely at the meta-level without saying a thing against their object-level claims is anti-epistemology.
Now, on to the ranting! The following are more-or-less a semi-random collection of tips I vomited out for trying to deal with politics rationally. I hope they help. This is a Discussion post because Mark said that might be a good idea.