Rosenfeld's What Democracy?

In response to both Rosenfeld’s What Democracy?, a piece aimed at demonstrating the necessity of abolishing the US Senate, and my colleagues responses to this same piece, I would have to say that I too am in disagreement with Rosenfeld that democracy in the United States would be better served by the abolition of the Senate.
However, I would like to first address an issue raised in the responses of others to this piece. One of the main arguments against Rosenfeld’s assertion is that the Senate serves an important purpose in that is ensures the representation of the interests of each state in the federal government; the general idea is that, were representation in the federal government to be solely proportional, the specific interests important to smaller states would get lost in the “majority will.” I take issue with this argument because it assumes that states have separate, distinct interests. However, I would contend that it is not the state, an entity which can be as varied in geography and peoples as the country itself, but rather other groups, such as farmers, industrialists, etc that have differing interests; we assume these interests fall along state lines, but in truth, they very often do not. As such, would it not be more effective to give a specific set of interest groups, entities that actually represent real issues, representation in Congress as opposed to these artificially constructed, perhaps archaic cartographic divisions?
Still the fact remains that I disagree with Rosenfeld that the US Senate should be abolished. He does an exceptional job in pointing out the “undemocratic” elements, or flaws with the institution, but fails to recognize the necessary purposes it serves. He doesn’t touch on the division of responsibility, or the fundamental tenet of checking the excesses of other governmental bodies. Furthermore, he criticizes the inefficiency of a bicameral legislature, a quality that in actuality is beneficial in ensuring the weighty nature of the law-making process. His argument is incomplete, in that is fails to address these and other fundamental issues in this centuries-old debate.