Political society of any kind requires that discourse be engaged in with pure intentions. The moment that the choice of words becomes subjugated to a preordained ideological outcome, political speech is no longer discourse. The purpose of political speech is to establish a course of action in harmony with the principles of society and the needs of the given circumstance. None of us can engage in political speech without preconceptions of some kind (preconceptions are what make us all "individuals"), but we can attempt to conform our speech to the truth of the matter under discussion and not conform speech to some extrinsic standard or conclusion provided in advance. Such action denigrates speech and makes real discourse impossible; it removes political speech even further from truth itself and pushes it deeper into the realm of opinion, feeling, and unreality.
These reflections are prompted by an article I saw today on an American news service that referred to persons illegally present in the US as "undocumented immigrants" instead of "illegal immigrants." I hadn't seen that phrase before so I attempted to ascertain its origin. As it turns out, certain persons had decided that the phrase "illegal immigrant" was too negatively charged and needed to be changed. Let us leave aside (for a moment) our views on the topic of illegal immigration, a topic of incredible complexity admits of no easy answers, and ask ourselves whether it is appropriate to try and modify discourse in this manner. The phrase "illegal immigrant" has a specific political meaning. Insofar as the people under question exist (politically) as immigrants, and insofar as the have not legally immigrated to this country, their being qua immigrant is qualified by its illegality. Contrary to the slew of bumper stickers that proclaim that "no person is illegal," the phrase "illegal immigrant" does not attempt to subject the fundamental personhood of anyone to a declaration of illegality. Rather, it simply states the (mutable) fact that the person's political existence as immigrant is illegal. This could be changed by amending immigration laws to allow such persons to legally immigrate, but as things stand now, the phrase "illegal immigrant" is objectively correct.
The phrase "undocumented immigrant" seems to suggest that the people in question merely are missing documentation. As such, it is a less precise description of what the political existence of these people actually are. While it is entirely true that they are undocumented, it is incomplete merely to say this. As a general rule we ought refer to things by their most important attribute to the matter at hand. The fact that these immigrants lack documentation is entirely predicated on the fact that they are not in the country legally. We aren't referring to people who came to the country legally and whose immigration papers were lost (a more accurate use of the phrase "undocumented immigrant").
Therefore, it seems clear to me that the appropriate phrase that ought to be used is "illegal immigrant" (again, note that we are making no judgments as to whether such immigration ought to be legal or illegal). To attempt to subordinate discourse towards a preconceived goal through altering the words that we use is horribly dangerous, even if employed towards good ends. It lowers the quality of our discourse and makes most of us less likely to think about what is actually being said. The corruption of discourse is the poison can undo any democracy, and I feel we are dangerously on the brink of this happening. The right calls politicians on the left variously "communists" and "nazis" (terms that are generally inaccurate) while the left calls politicians on the right "bigots" and "racists" (also terms that are generally inaccurate). The more that people believe these insults the less likely they are to listen to each other. And once no one is listening to anyone, democracy is no longer possible.
We should always insist on clarity and precision in our discourse, even when such clarity and precision work against the goal we wish to achieve.