Political science is a science. Don't be confused by the variety of research schools, the diversity of hypotheses, the dearth of experiments, and the inability to draw binding conclusions from analysis. Don't be put off by the absence of universally accepted general laws of politics. Certainly, you have no reason to assert that a science of politics is impossible. Following Weber and Geertz, you might contend that the social sciences need to include methods not found in the physical sciences, but that is not a reason to deny the label "science" to the study of politics.