Presidential candidates, and congress may sometimes push for more research in a particular field or a big project like the human genome or the precision medicine initiative or the cancer moonshot. Sometimes politicians will put out a press release about a particular study in social science, say, something about teen pregnancy rates and sex ed and prophylactics, and then use that as a sound byte for social conservatives. They might do earmarks for their home district (I think they got rid of earmarks though obviously there are other huge issues). But politicians do not get involved in the awarding of grants to this university or that.