There is no random sampling.
The population of interest is actually the whole US adult population, from which a random sample has to drawn. If the sample is not random, it is not possible to infer conclusions, from the data generated during the study, to the whole population.
A gender distinction has been made when selecting the individuals for the sample in order to reach 1000 inviduals that satisfy the condition of being males and other 800 that satisfy the condition of being women. Therefore, the sample individuals have not been randomly drawn from the population of interest if a certain number of them is conditioned by a certain characteristic. Therefore, it is impossible to infer conclusions about political memberships in terms of gender for the whole population with a non-random sample.