Maybe art with a political motive is art and utility married - but that doesn't sound quite right, let's define utility:
- The quality or condition of being useful; usefulness: “I have always doubted the utility of these conferences on disarmament” (Winston S. Churchill).
- A useful article or device.
Perhaps art with a political motive has a function, it moves people, it communicates - this differs from a utility - a utility has a practical application. Is Marx completely ignorant to say that nothing without utility can have value? He wrote a book that does not have a utility, only a function. Although in fact a manifesto differs from a book in that it has a practical application and so has a definite utility.