How did the Sherman Antitrust Act affect industrialists like Rockefeller?
At a time when businesses were running separate of government action and when industry controlled so much of American life, the Sherman Antitrust Act was a significant piece of legislation in attempting to control that which existed as uncontrolled. The so- called "Titans of Industry" such as Rockefeller, J.P. Morgan, and Andrew Carnegie operated in a realm outside of politics, social sensitivity, as well as any other element. These individuals were considered to be the "best and the brightest," and were also the most powerful because, simply put, no one could control them. The Sherman Antitrust Act was one of the first steps to ensure that government could prove to possess some level of control over these forces. In ensuring that the idea of illicity monopolies harm the American free market system, and laying down prerequisites that established business cartels and a crushing of competition, the Act was significant in that it represented a form of government check on business practices. It showed Rockefeller and Standard Oil, as well as other conglomerates, that they could not influence the marketplace in order to consolidate their own power. The elimination of sitting on other companies' boards, for example, and targeting behavior that "unfairly tends to destroy competition itself" is where the greatest impact of this legislation was felt by those in the position of economic power, such as Rockefeller.
Though noble in intent, it's fair to say that the Sherman Antitrust Act was remarkably ineffectual in practice. A law is no use if there aren't appropriate enforcement mechanisms in place to make it work, and this was the Act's fatal flaw. Over the legislation's lifetime, it was seldom enforced successfully, and even when it was, as in one notorious case, it was used against striking labor unions for restraint of trade.
Simply passing a law against trusts and its associated monopolies didn't lessen the immense political power and influence of the robber barons and captains of industry such as John D. Rockefeller. We should bear in mind that the Harrison Administration was Republican and, as such, closely linked to big business interests. Intense lobbying by those affected led to a somewhat creative interpretation of the Act's provisions. Expensive, high-powered lawyers hired by big business were easily able to drive a coach and horses through the Act's many loopholes. The vaguely-worded legislation failed even to define adequately what a trust actually was. And given that the breaking up of trusts was the Act's main purpose, this was a serious drawback to its effectiveness.