As others have pointed out, although the ideological extremes try to control the agenda, the success of national elections relies on the middle, which dictates moderation, and if you want to get anything accomplished, reality-based pragmatism, which is all but missing in most ideological battles.
The current vile incarnation of the GOP, so dominated by its extreme elements seems to be quite an illogical aberration. They are already so far down the path of “purification” that I seriously question whether they can pull back from that precipice at all. For one thing, too many of their “base” seem to take the wrong lesson from 2006 & 2008 - that they weren’t extreme enough and their only strategy at this point seems to be to oppose everything the president or democrats want to do or to do nothing at all, simply thinking that they will magically gain seats in 2010, solely because there are historical patterns for that…without any contemplation or broader understanding of the true hole they have dug for themselves.
Although politics can be very fluid, unless there are major changes, it looks more likely that they are headed towards more devastating losses in 2010…and the question then will be - is it too late for them to learn the lesson…or will there even be enough rational people left in the GOP to care?
I think they are so tarnishing their “brand” that whatever re-emerges as the 2nd major party might be renamed something different - even if it contained many of the same players.
I already hear many “right-wingers” I know no longer call themselves Republicans…which is funny, because it seems that by starting down the road to “purification”, ironically, it is not “pure enough” for the different extreme factions that now have dominant voices. Will even these people hang on to a tarnished brand, or will they flee to increase the ranks of existing Libertarian Party or Constitutional Party memberships…or create another one like that?
So therefore, I do think the GOP is headed down the road to becoming the Whigs. I think 2010’s elections will just accelerate that. Once it becomes clear that they are truly no longer a national party, I think a whole host of other dynamics and factions will come into play for awhile and eventually a strong second-party will emerge.
I do think in that period, it is likely to see a possible split-off of the far-left or the center-right-moderates, but I think when everything has settled back to two major parties, centrist voices will end up dominating, but the country and politics as a whole will have shifted leftwards from where they have been over the past several decades.