The New York Times this morning has a review by George F. Will of two books about conservatism. It's worth reading, if you're interested in the philosophy of conservatism, though most of it is well-trod ground.
The question of "What is conservatism" is highly relevant, even if it's unanswerable.
Republicans campaigned with conservative principles, then, once they gained power, shed the principles faster than a john sheds clothing. So it's relevant to ask, "What are the true conservative principles that ought not be shed?" Is it libertarianism? Social conservatism? Just good old fashioned tradition?
I won't even attempt an answer here. I tend to believe that true conservatism is libertarianism that has roots in the natural law. I also tend to think that true conservatism tends to be Catholic. Many--including conservative non-Catholic friends and Catholic liberal friends--would recoil at this, but it's no surprise that many conservatives--Jeffrey Hart, Russell Kirk, Frank Meyer, Willmoore Kendall, Richard John Neuhaus, Earnest van den Haag, even Jeb Bush--are Catholic converts, and many others--like James Burnham (a lapsed, but later returned, Catholic) and the Buckleys--were raised Catholics, and still others, like Murray Rothbard, had great respect for the Catholic Church.
I believe conservatives have frequently turned to the Catholic Church because only the Church is able to handle the crux of the problem of society: linking God's immutability, including His laws, to society's mutations.
Society is, by nature, a whirling mess. Every social or political issue implicates, at some level, every major area of study: science, history, philosophy, theology, literature, psychology, sociology, hermeneutics, archaeology–the list with its sub-lists could go on for an entire page. No one can accumulate all the past wisdom and keep on top of the accruing wisdom. Only the Church, the Catholic believes, with its 2,000-year continuity, legion of scholars, humble but wise bishops, an authoritative leader in the Pope and, most importantly of all, its divine sanction (Mt. 16:18) and the guidance of the Holy Spirit can reach definitive conclusions. And only the Church, with its numerous followers, solid history, hierarchy and refusal to rush to any conclusions, can command the universal respect necessary to put its theoretical conclusions into effective practice. Authority, tradition, deliberateness: It's a natural fit for the conservative.
All this, incidentally, is not intended to denigrate the contributions or efforts of non-Catholic Christians. As C.S. Lewis demonstrated, all Christians participate in this Christian tradition. Yes, I believe Catholics participate in it better, but I mean no disrespect to other Christians. I merely believe that, as a conservative institution, the RCC is number one. The theological merits that separate the Christian churches, in other words, are scarcely touched by this post.