The word is invoked to refer to a number of surprisingly diverse worldviews -- and politicians take advantage of that.

Roughly two-fifths of Americans call themselves "conservative." What do they mean by the word? It depends. And during a Republican primary, that can be problematic. Every candidate is vying to be the standard-bearer for conservatism, and exploiting the fact that its meaning is variable.

Thus the need for this exercise.

What follows is an attempt to tease out the many different worldviews Americans are referring to when they invoke the word conservative -- and then to figure out which of these worldviews best describe Mitt Romney, Newt Gingrich, Rick Santorum, and Ron Paul, the choices before Republicans. Bear in mind that what follows aren't my definitions of conservatism, but what various Americans mean when they use the word.

An aversion to rapid change; a belief that tradition and prevailing social norms often contain within them handed down wisdom; and mistrust of attempts to remake society so that it conforms to an abstract account of what would be just or efficient. A desire to preserve the political philosophy and rules of government articulated in the Declaration of Independence and the U.S. Constitution. A belief that it is imperative to preserve traditional morality, as it is articulated in the Bible, through cultural norms. A belief that it is imperative to preserve traditional morality, as it is articulated in the Bible, using cultural norms and the power of the state. An embrace of free-market capitalism, and a belief in the legitimacy of market outcomes. A belief that America is an exceptional nation, a shining city on a hill, whose rightful role is leader of the free world. A belief that America should export its brand of democracy through force of arms. The conviction that government should undertake, on behalf of the American polity, grand projects that advance our "national greatness" and ennoble our characters. An embrace of localism, community and family ties, human scale, and a responsibility to the future. A belief that America shouldn't intervene in the affairs of other nations except to defend ourselves from aggression and enforce contracts and treaties. A desire to return to the way things once were. Affinity for, identification with, or embrace of Red America's various cultural cues. (For example, gun ownership, a preference for single-family homes oriented around highways rather than urban enclaves organized around public transit, embrace of country music, disdain for arugula and fancy mustard, etc.) Disdain for American liberalism, multiculturalism, identity politics, affirmative action, welfare, European-style social policies, and the left and its ideas generally. A desire to be left alone by government, often coupled with a belief that being left alone is a natural right. A principled belief in federalism. The belief that taxes should be lower and government smaller. The belief that the national debt and deficits put America in peril. The belief that whenever possible, government budgets should be balanced. Consciousness of the fallibility of man, and an awareness of the value of skepticism, doubt and humility. Realism in foreign policy. Non-interventionism in foreign policy.

Granting that any list of this kind is imperfect, I contend the foregoing is sufficient for our purposes. So where do the presidential candidates I've mentioned fall?