Liberalism in IR theory emphasizes individual rights, cooperation, and progress through international institutions. It assumes rational actors can make decisions based on mutual benefit, advocating for the spread of liberal values like human rights and free trade. Neoliberalism evolved from classical liberalism, focusing on the role of international institutions and norms in shaping state behavior. It recognizes the need for global governance in an interconnected world, while critics argue it prioritizes powerful states' interests over developing countries.