Is "pragmatism" an alternative to liberalism and conservatism?

I've heard it suggested that Barack Obama is neither a liberal nor a conservative, but a "pragmatist." Google "obama pragmatist" for a smattering of evidence, typified here. I have heard the claim both upheld and challenged, by both his supporters and his opponents, as both a criticism and an accolade.

For some, pragmatism suggests a lack of dedication to ideals, "flip-flopping," and a politician's proclivity for saying anything to get elected. People who think of pragmatism this way might cite as evidence Obama's broken promise to only accept public financing for the general election if John McCain would agree. He initially spouted the ideals, these people would say, but when a more pragmatic option came up, he jumped on it.

One friend, a devout liberal, too liberal for the Democratic party, told me several months ago that her message to Barack can be summarized, "Quit pandering and get back on the Left where you belong!" (This was right after Obama spoke in favor of the Supreme Court's decision to overturn the D.C. gun ban. Her allegation became even harsher when Obama began to support off-shore drilling.)

For others, pragmatism is a rare breed of politics based on consensus, utilitarianism, and an open mind. "Reaching across the aisle" is the phrase most often used to express this idea of pragmatism, and by that standard John McCain sought to portray himself as a pragmatist, as well. In fact, McCain frequently charged Obama with being the "most liberal Senator" and failing to provide convincing evidence of having "reached across the aisle" and "challenged his Party's leadership."

A similar but distinct definition of a pragmatist places "pragmatism" somewhere in the middle on the continuum of "idealism" to "realism." By this definition, the candidates have occasionally landed at different points along the continuum. For example, after Russia's invasion of Georgia, McCain declared that Russia should be kicked out of the G-8 as punishment for their unlawful actions; Obama responded that even though he condemned Russia's actions, kicking them out of the G-8 would only further isolate them and make future negotiations more difficult. McCain the idealist, Obama the pragmatist.

Still other definitions remain. Pragmatism is sometimes considered a disavowal of ideology and a commitment only to truth, common sense, fact, and expert advice. Nonpartisan problems, people who buy this idea of pragmatism would say, should be solved with nonpartisan solutions. Put the politics aside and get something done, they say.

Which of these definitions are more correct than others? Is the descriptor "pragmatist" an apt one for Barack Obama? These questions are difficult to answer with any certainty, and it doesn't matter. When politicians use the term "pragmatism" to describe their political philosophies or their approaches to an issue, I usually regard it as a meaningless rhetorical strategy, meant to suggest that the issues important to them are "beyond politics." (My response: no issue is beyond politics.) There is much to be admired in being led by the spirit of pragmatism, just as their is much to be distrusted, but the truth is that pragmatism is neither the exclusive domain of liberals nor conservatives, nor is it accurately conceived as an alternative to either.