Now, I see that Reinhold Niebuhr wrote an essay some time ago that talks about some of the different trends and manifestations of liberalism in the US, the UK, and France. He specifically focuses on how the original liberals centuries ago were reacting to aristocratic society (which doesn't exist today, so liberalism had to shift its focus to remain pertinent), and he goes on to talk about how different conditions in the three countries led to somewhat different outcomes. He succinctly sums up the shift:
The new conservatism about which one hears so much these days may claim a right to the title of "liberalism" on the ground that its promise of gaining justice through economic liberty is actually closer to the old classical economic liberalism than the new liberalism is. On the other hand if the concern for justice is the primary hallmark of liberalism, those who want to bring economic enterprise under at least minimal control have as much right to this title as those who want to preserve economic freedom.
And although the article was originally published in 1970, it seems right on the mark today:
At this moment, the old debate between freedom and control of economic life has narrowed to a very small difference in emphasis between the Tories and the Labour Party, a difference which has become slight in all modern nations.
In other words, as Ralph Nader would put it, the difference between the Democrats and Republicans is one of Tweedledum and Tweedledee, and (Niebuhr would add) that is because our major political parties today are all descendents of liberals (except for the Greens, I would add).
But the most fascinating part comes near the end, where Niebuhr seems to explain why the Republican Party (i.e. conservatives) seem to have so little to offer these days other than patriotism and partisan politics (= filibustering Obama):
There is, unfortunately, no social locus in America for a valid "conservative" philosophy. The more parochial part of the business community is bound to develop a conservatism in which a decadent laissez-faire liberalism in domestic politics is compounded with nationalism.
Of course, the word conservative itself is related to conservation, so another essay could talk about how a truly environmental party would garner support among religious groups and pro-business politicians to protect God's green earth (in the case of the former) and ensure sustainable growth (in the case of the latter). That would certainly be an impressive social locus for the Republicans.