In the Miers case, it could be argued that bloggers on the right saved the president from making a critical mistake, and nudged him onto the path that ultimately led to a enormously significant part of his presidential legacy. But bloggers on the left are pushing their party into a difficult wilderness. The angry "net-roots" denounce any Democrat for deviating from their agenda, without a moment's thought of trying to run for re-election with a liberal record in West Virginia, North Dakota or Nebraska.
Republicans can find strength and success by listening to their like-minded bloggers; Democrats can find strength and success by ignoring theirs.
Interesting analysis of the role bloggers play for each political party with a special focus on the Harriet Miers and Samuel Alito nominations.