In my undergrad, I grappled with the issue of the Senate being undemocratic in the sense that its votes are not proportional to state population (as the House is, though not completely). The filibuster increases this undemocratic leaning by allow 41 senators, which could represent a small minority of Americans, to block a vote on nearly any issue. In a country of 304,059,724 (estimated as of July 2008), Senators representing the twenty states with the lowest population plus one senator from the 21st lowest population state could conceivably hold nearly any bill from ever receiving a vote. Seven of these states have less than a million residents, eight have between one and two million residents, and the final five each have less than three million residents. The 21st state, Iowa, has just over three million residents. Combined, the population of these twenty states, plus half of Iowa, adds up to 32,637,771 or just over ten percent of the U.S. population. The fact that nearly 90 percent of the population can be outvoted by this small minority clearly indicates that at the very least dissolution of the filibuster is something to consider, if not wider reform of the system for electing Senators.
Luckily, getting rid of the filibuster simply requires a majority vote, while any larger Senate reform would likely require amending the U.S. Constitution. Some will argue that the filibuster has been used in the past to moderate debate and force compromise. They will say that despite its undemocratic nature, it provides some protection from majority tyranny. While I accept that protection of the rights of the minority are fundamental under any legitimate democracy, requiring super-majorities to even be able to vote on a bill often hampers the policy-making process through allowing powerful lobbyists to influence the votes of a few against the will of the many.