In 1846 he founded the Associations for Free Trade and used its journal, Le Libre-Échange (“Free Trade”), to advance his antiprotectionist views. In a well-known satiric parable that appeared in his Sophismes économiques (1845; Sophisms of Protection), Bastiat concocted a petition brought by candlemakers who asked for protection against the Sun, suggesting that candlemaking and related industries would greatly profit if the Sun were eliminated as a competitor in furnishing light.

Bastiat's petition has become so well known that modern economists often use it in their own defenses of free trade; indeed, Paul Samuelson (Samuelson, Paul) put it at the head of one chapter in his best-selling textbook, Economics (1948). Bastiat also emphasized what he called the “unseen” consequences of government policy.

During the revolutionary years 1848–49 he wrote against the rise of socialism, which he identified with protectionism. It was primarily his campaign against socialism and communism that won him a seat in the Constituent Assembly in 1849 and in the subsequent Legislative Assembly of the same year. Economic theorist Joseph Schumpeter (Schumpeter, Joseph A.) called Bastiat “the most brilliant economic journalist who ever lived.”