This is one of those broad, obvious questions that becomes more and more complicated the more you actually try to think it through. The totally unsatisfying answer, of course, is yes and no.
I have been trying to put together some sort of a coherent post about this and I cannot seem to get it straight, so I am going to post what I have and invite other opinions.
The first point here is that some of the fundamental questions the GOP faces today are very similar to those the Democratic Party faced in George W. Bush's first term: How much ground do you cede to the majority party? How much should you cooperate with a popular opposing-party president?
The Republican Party's answers to these questions, so far at least, have been "none" and "none." This has created visible delight among many Democrats, who see it as a way of doubling down on ideological purity that is driving out moderate pols and citizens from the GOP. Utah Gov. Jon Huntsman's decision this weekend to join the Obama administration is just the latest example, and this Politico piece has some good context on the killing-off-of-Republican-moderates situation.
For many on the right, though, the argument is that the Republican Party must use its time in the wilderness to become a true opposition party. Something like a vote on the economic stimulus package is a question of principle, and if the GOP is ever going to regain public support it needs to have a spine and not bend to political winds.
If you think back to when Bush was riding high -- or even to Al Gore's 2000 campaign -- those are pretty much precisely the arguments made by a lot of people on the left, aren't they?
The answer is "yes," but there are some important differences. The Netroots -- following the lead of the very strategically minded Kos -- always tolerated a pretty big tent for the Democratic Party provided candidates were regionally appropriate. This explicitly meant supporting conservative Democrats in races liberal Democrats couldn't win, and basically the left-wing base accepted that as a reality. The fact that the Democratic base tolerated pro-life candidates in various races all over the country, for example, amounts to massive concession of ideological purity on the left. And yet this type of moderation has largely been understood to be a good thing for the left insofar as it helped build Democratic majorities in Congress.
In the current debate on the right, I see virtually no acknowledgment that the Republican Party ought to allow for regional variation in its candidates. Tell me if I am wrong, but all I see is a debate between "conservatives" and "moderates" -- no real discussion of how a Republican might have to take somewhat different positions to win in the northeast or the Midwest, or increasingly in the Mountain West. I would think that is the discussion Republicans will have to have if they lose in 2010, but maybe I am wrong.
For my part, I certainly agree with the conventional wisdom that the more the Democratic Party encroaches on the moderate wing of the Republican Party, the better off Dems will be and the worse off GOPs will be. But it seems to me there is something to the right's have-a-backbone argument, just as there is clearly some political value in just the pure esprit de corps that comes from being a loud-and-proud opposition party.
So my answer is that while the GOP is clearly adopting some of the Howard Dean-era Netroots political strategies, it remains to be seen whether it will at some point choose to a.) moderate the party at the national level, which the Netroots never really wanted Democrats to do, or b.) adopt some form of a strategic long-game and tolerate regional variations, a strategy with which the Netroots have been remarkably effective. Or, the Republican Party could c.) do neither, and test the political value of ideological purity only, or d.) try something else that I haven't thought of. Anyone have thoughts on which of these is most likely, and/or which would be most effective?