Antitrust research bleg:

One of the reasons for the enactment of the antitrust laws was to safeguard political freedom by preventing the formation of large corporations powerful enough to control the government. Taft, in his book The Anti-Trust Act and the Supreme Court (written in 1914, after his presidency but before he joined the Supreme Court), said the Sherman Act had attacked methods of "suppressing competition and controlling prices" which "had resulted in the building of great and powerful corporations which had, many of them, intervened in politics and through use of corrupt machines and bosses threatened us with a plutocracy" (p. 4).

Does anyone know of an economicsy, perhaps public-choicey, treatment of the same point, where antitrust emerges as a second-best optimum to prevent corruption or excessive corporate political influence?