A recent Washington Post article used a plural verb with the noun politics. The same article used a singular verb in a parallel example, and a reader pointed out that we were inconsistent (true) and that the latter was correct (false). Observe:
Politics is a noble pursuit. My politics are none of your business.
Economics was her first choice for a major, but she opted for business. The economics of the idea make it unfeasible.
Genetics is a multibillion-dollar enterprise. Our genetics conspire to make having children a very bad idea.
All of the above are correct. Citations? I have plenty.
The Washington Post stylebook:
Words ending in -ics, such as politics, economics and tactics, may be singular or plural, depending on context: Politics is my business. Their politics are dirty. Tactics is a science. His tactics are irrational.
Garner's Modern American Usage:
Politics may be either singular or plural. Today it is more commonly singular than plural (politics is a dirty business ), although formerly the opposite was true. As with similar -ics words denoting disciplines of academics and human endavor, politics is treated as singular when it refers to the field itself (all politics is local) and as plural when it refers to a collective set of political stands (her politics were too mainstream for the party's activists).
The Associated Press Stylebook:
Usually it takes a plural verb: My politics are my own business.
As a study or science, it takes a singular verb: Politics is a demanding profession.
The New York Times Manual of Style and Usage:
Politics can be singular or plural. Use a singular verb when the word refers to an art or science: Politics is the study of government. But use a plural verb in reference to practices: His politics are contemptible.
The Wall Street Journal Guide to Business Style and Usage:
It can take a singular or plural verb. But as an art or science, it is singular: All politics is local.
I would quarrel only with the emphasis of the Garner and WSJ entries (I think most writers and editors would start with a bias toward the singular and would need a prod in the plural direction) and with the use of "All politics is local" as an example of the discipline usage as opposed to the practice usage. Quite the contrary, I think it's a tricky exception to the rule. The politics in "All politics is local" look(s) to me identical to the politics in "My politics are none of your business," but the former expression, attributed to Tip O'Neill, is well established, and to give it a plural verb invites the reader to interpret it as referring to each and every "politic" being local.