The Montagu Principle: Incivility decreases politicians' public approval, even with their political base.

M. W. Montagu asserted that, "civility costs nothing and buys everything." In the realm of social judgment, the notion that people generally evaluate civil people more favorably than uncivil people may be unsurprising. However, the Montagu Principle may not apply in a hyper-partisan political environment in which politicians "throw red meat to their base" by unleashing uncivil, personal attacks against their opponents, satisfying the aggressive desires of their most hyper-partisan supporters, and thus potentially redoubling their approval among them. We conducted 2 longitudinal/observational studies of U.S. Congress and President Trump, and 4 experiments (N = 4,837) involving real exchanges between President Trump and his adversaries and a speech by a fictitious politician. Civility helped or did not affect-but never harmed-the reputation of the speaker, supporting the Montagu Principle. Even self-identified "diehard supporters" of President Trump, for example, evaluated the president more favorably after he responded with civility to a personal attack. Uncivil remarks uniquely diminished the speaker's reputation, and had little impact on the reputation of the targets of the attack, the perceived winner of the verbal exchange, the reputation of the speaker's party, or the sense that the country is moving in the right direction. Incivility made the speaker seem less warm and did less to affect perceptions of dominance or honesty. This warmth deficit explained the reputational costs of incivility. (PsycINFO Database Record (c) 2018 APA, all rights reserved).