Uncover abuses in government
One way thing that the US could do about monopies is regulating them by breaking a monopoly up. In certain cases, government may decide a monopoly needs to be broken up because the firm has become too powerful. This rarely occurs. For example, the US looked into breaking up Microsoft, but in the end the action was dropped. This tends to be seen as an extreme step, and there is no guarantee the new firms won’t collude.
