The supreme court decision under John Marshall leadership have extended federal powers, but not too much in the sense of destroying the federalist idea that brought the United States together. Marshall was guided by a strong commitment to judicial power and by a belief in the supremacy of national over state legislatures. His judicial vision was very much in keeping with the Federalist political program in line with the constitution.
It can be argued that someone not elected should not have power to shape government and law through the Expansion of the Judiciary in 1801, but the Marshall Court, and this decision in particular, established the principle of "judicial review" whereby Congressional laws and executive actions may be judged by the Supreme Court to be within the bounds of the Constitution.
It is definitely not appropriate that a political party ideology is implemented through the judiciary, however, In keeping with John Marshall's Federalist views, they generally favored strong government action and especially supported the supremacy of the federal government over state authorities as long as it was constitutional.
In short, Libertarians believe the government should never violate an individuals rights (socially liberal), and should be extremely limited its power, especially in regards to the economy (economically conservative).
Carried forward, Libertarians generallysupport gay rights, a woman's right to choose ("pro-choice"), and an individuals privacy (opposed to the Patriot Act, and to a degree also opposed to the CIA). Anything that expands the individuals' rights, Libertarians support.
Economically, Libertarians generally believe that Capitalism should be unregulated. There are some blatant problems with monopoly and scams (i.e. Ponzi schemes), and a certain number of Libertarians believe there ought to be some regulation.
In a similar vein, Libertarians generally are opposed to the power of the monopoly called government. As a political philosophy, Libertarians believe the government should exist only to protect the liberties of its citizens. A strong military is acceptable, but Libertarians favor the philosophy of the founding fathers - nonintervention.
These "policies" are only as I understand them, and should not be taken as representative of all Libertarians.
