Wiktionary defines politics as, "the practice of responding to conflict with dialogue" [http://en.wiktionary.org/wiki/politics]. This appears to be the most appropriate definition for the context of work and careers but the everyday labelling of politics within a company often has negative connotations, i.e. political behaviour = unhelpful and obstructive.
The labelling of certain behaviour as political also depends on the perspective of the people involved. What may be obstructive from one viewpoint can just as easily be seen as essential to survival from another.
Politics and political behaviour occurs within an organisation where there are differences in strongly held opinions and/or beliefs. Response to these differences through dialogue is labelled by some as political. For the individuals doing the labelling, the desire to act or change the agenda is felt more urgently, hence the frustration that more dialogue causes.
Ultimately, the success of a business and the individuals within it presents the acid test for the health and continuity of its political environment.
And if that is an unsatisfactory conclusion, then let the debate continue...