The article analyses evaluativeness role in implementing the American pre-election TV ads strategies in the diachronic aspect. Scientific originality of the paper is conditioned by the fact that dynamics of the pre-election TV ad genre is still poorly investigated and also by the fact that the genre dynamics is considered taking into account the evaluative component of the pre-election discourse distinguished by a high pragmatic potential. The study is conducted by the material of three corpuses of the American pre-election TV ads classified according to the historical periods: 1952-1972, 1976-2000, 2004-2020. The research findings are as follows: the author identifies changes in the choice of evaluation objects, reveals the growing role of certain strategies using evaluation as a means of manipulative influence. The conducted analysis allows concluding on prevalence of negative evaluation in the modern American pre-election discourse.