Marx, easily. Rothbard's anarcho-capitalism would be useless in a post-apocalyptic wasteland where you need massive coordinated reconstruction efforts, not debates about property rights while people are starving.

Marx's focus on collective action, material conditions, and industrial organization would actually help rebuild infrastructure and production. You need planned coordination to get power grids back up, not free market theories.

Rothbard's ideas only work when civilization is already functioning smoothly. Marx's are built for revolutionary change from the ground up.