Pierre Elliott Trudeau – radical progressive or unavowed socialist? His legacy remains divisive. Most scholars portray Trudeau’s ties to the left as evidence either of communist affinities or of ideals that led him to found a progressive, modern Canada. The Constant Liberal traces the charismatic politician’s relationship with left and labour movements throughout his career. Christo Aivalis argues that although Trudeau found key influences and friendships on the left, he was in fact a consistently classic liberal, driven by individualist and capitalist principles. While numerous biographies have noted the impact of the left on Trudeau’s intellectual and political development, this comprehensive analysis showcases the interplay between liberalism and democratic socialism that defined his world view – and shaped his effective use of power. The Constant Liberal suggests that Trudeau’s leftist activity was not so much a call for social democracy as a warning to fellow liberals that lack of reform could undermine liberal-capitalist social relations.