Liberalism has meant many things to many different people over the centuries. During the days of the American Revolution, in its quintessential classical form, it stood for individual rights, participation in the free enterprise system, and inalienable civil liberties. Utilized most notably by Thomas Jefferson while drafting what would eventually become our Constitution, it serves an integral historical role in the socioeconomic fabric of our nation.
However, since the dawn of the Great Depression, liberalism has essentially abandoned its former principles in favor of currying support with economically depressed and ethno-social minority voters. This shift picked up considerable steam during the 1960s, in which a slew of federal macroeconomic interventionist programs were enacted for the purpose of creating a more equitable society. After most of these went on to become abject failures, for example, affirmative action, which forced many employers to hire based on stringent racial quota systems, liberalism's fiscal policies summarily fell out of favor with the general voting public. They were retooled and revitalized with mildly conservative ideas by a group of forward thinkers during the early 1990s, however, and produced a booming economy which remained remarkably dynamic throughout the remainder of the decade. By the time the late 2000s occurred, though, liberalism had once again resorted to interventionism, an action which produced an incredibly strong conservative electoral backlash that effectively fractured its near-total dominance on Capitol Hill.
Despite its extremely turbulent economic record, post-Depression liberalism's undying adherence to the ideas of social justice have ensured it some degree of popularity with the mainstream of the United States' body politic. Indeed, many of its stances on social issues, such as the ceaseless pursuit of equal rights for all, serve as efficient counterweights to some of the lesser ideas presented by authoritarian conservatives.
Modern liberalism's views on national security matters vary widely; a great deal of its adherents favor moderately hawkish policies, while others are self-declared pacifists, and yet more are somewhere in between. As there is very little consistency in this regard, it is most difficult to pin down exactly where modern liberalism lay; perhaps it can be stated that it is, at its very core, a catchall.