Our tradition believes in “support that which we believe in and fight no one.” With this philosophy and the added caveat of knowing the perfection of all beings, my job is to speak to personal values and morals while honoring where that teaching may take you as an individual.
If we take seriously the concept that faith affects one's "real life," then it seems that part of a preacher's job is to dicuss issues (some of which may be political) with the congregation.
I think it is OK for a pastor to talk about politics to make a point in their sermon, if they can use the topic to help illustrate their point. If using Bill Clinton as an example to illustrate the consequences of lying about adultery will help get the point across, then it is fine.
Over the last week, Americans learned that the Internal Revenue Service targeted some 500 conservative groups for extra scrutiny, some of which included the words "Tea Party" or "patriots" in their name. Several reports say that the agency has also targeted some Christian organizations, going so far as to demand the content of members' prayers.