It shouldn’t be too hard if you define your terms and stick to them. Take the definition of politics as something like the study of relations between people or groups of people. Define art either in a sufficiently restrictive manner to provide yourself with focus, or so broadly as to encompass practically anything produced by people. Then write about how one group’s work is relating to, or commenting on, or influencing, or getting a reaction from another group.
There’s an endless supply of things you could focus on. To rehash well-covered (but relatively modern) ground, read some on Dadaism and see where that takes you. Or think about Sasha Baron Cohen’s material, or Lenny Bruce. Heck, Maine Governor LePage’s mural removal could be worked into your essay as a near-literal art/politics nexus.
But an example that’s cooler than those – I just watched (and highly recommend) Exit Through the Gift Shop. I had thought it was a retrospective of Banksy’s material, which I’ve “stumbled upon” on internet sites and always enjoyed. I expected to see some Banksy graffiti, listen to some interviews with him, and just spend an enjoyable hour and a half on a (relatively) current topic. But, oh, it was so much better than I expected, ending up – IMHO and interpretation – as a meta-commentary on an entire part of the art world.
Or, you could always reject the premise and go the other way, which might require different definitions. I hope some of that is helpful, at least providing some ways in for thinking about the topic; seems like an assignment full of potential to me.