Thomas Robert Malthus was an English economist and influential scholar in the field of political economy.
Malthus created this theory of connection between the increase in supplies for the population leads to happiness, which leads to population growth, which leads to a decrease in supplies. It's this sort of paradoxical theory about politics and economy, where he also found that populations use this abundance of supplies to grow population rather than maintain stability.
This ties into Urinetown because while Cladwell is trying to keep the supplies they have, the rebellion is trying to make use of those supplies. One could say that Cladwell is trying to keep the population from falling into this pattern, but he's also forcing them into what is called a Malthusian catastrophe: where the lower class is more susceptible to war, famine, and disease.
Malthus wrote in opposition to the popular view in 18th-century Europe that saw society as improving and in principle as perfectible.