Social justice education (SJE) is a ubiquitous, if inconsistently defined, component of contemporary education theory and practice. Recently, SJE has come under fire for being politically biased and even "brainwashing" children in the public education system. In a liberal democracy such as our own, it is important that state-sponsored actions and essential public goods can be justified to all citizens, not only to those with a particular set of beliefs. To defend SJE against its detractors, therefore, it is insufficient to argue over the concrete values that SJE seeks to inculcate; it is instead necessary to develop a philosophical argument situating SJE within a conception of democratic liberalism. This article provides such an argument by reviewing competing conceptions of liberalism, analyzing the political culture in Canada, and applying an interpretation of comprehensive liberalism to specific educational initiatives. Rather than defining or justifying all instances of SJE, the goal is to show how some, but not all, substantive political views can be coherently espoused in the Canadian education system without turning into "brainwashing." Five specific criteria are offered for discriminating between legitimate and illegitimate forms of education within Canadian liberalism. I use these criteria to show that much of what we recognize as SJE is justifiable, not because every citizen endorses the concrete values it represents, but because and only insofar as it reflects a democratic political culture that does.