Critics of my suggestion that the country may be better off, from a conservative/libertarian point of view, if the Republicans lose the House of Representatives make three main arguments:
1. The claim that incoming Democratic committee chairmen will cause greate harm.
2. The danger that the Republicans will react to defeat by moving to the left.
3. That a Democratic House might defund the Iraq War, causing a catastrophic defeat.
I don't think that any of these points are compelling enough to justify holding off on throwing the bums out. Yes, it is true that the Democrats are likely to appoint some very liberal and (in some cases) dubiously competent committee chairs. But the Democratic House majority is likely to be narrow, and the committee chairs' more extreme proposals could be killed by the full House, where the swing voters will be more moderate centrist Democrats. Any far left bill that does clear the House stands to be killed by the still-GOP controlled Senate. If worse comes to worse, President Bush could veto it. Presumably, he will be far more willing to veto dubious Democratic bills than those of his fellow Republicans. Finally, as commenter Angus points out, some of the Republican committee chairmen are not much to write home about either.
I am also skeptical that the Republicans will react to defeat by moving to the left. If the Republicans lose, it will almost certainly be because of the widespread (and at least in part accurate) perception that they have been foolish and incompetent. As I have documented elsewhere, most voters - particularly swing voters - have only very limited knowledge of ideology and are unlikely to respond to ideological changes at the margin. To paraphrase Michael Dukakis, a Republican defeat in 2006, if it happens, will be far more about competence than ideology, and GOP political strategists will be able to figure this out. Moreover, if the GOP moves any further to the left than it already has on size of government issues, it risks a backlash from conservative activists (who care far more about ideOlogy than most ordinary voters do). Finally, it is worth remembering that the last three major GOP defeats in national elections - 1964, 1976, and 1992 - led the Party to react by moving to the right, not the left. Smaller defeats in 1982, 1986, 1996 and 1998 also did not cause much leftward movement.
I highly doubt that a Democratic House would defund the Iraq War. Democrats are deeply divided about what to do in Iraq. Enough of them oppose an immediate withdrawal that any effort to defund the war would almost certainly fail to pass in a House of Representatives with only a small Democratic majority. Even some very liberal Democrats might hesitate to vote for such a measure, since doing so would saddle the Party with the blame for the resulting military defeat if it passes. On the other hand, the Democrats will probably be more willing than Republicans to provide some tough adult oversight for the Bush Administration's far from optimal use of the funds already allocated for Iraqi reconstruction.
In short, bring on Nancy Pelosi!