If democracy is more about process--how decisions are made and who makes them--than about the policies that result, the United States Senate has become not merely dysfunctional, but an actual threat to the functioning of America's system of government.
That threat is exemplified by two features of the Senate's rules: the filibuster and the "hold." While both procedures can serve legitimate and valuable ends, and each has a proper place in the legislative arsenal, neither is constitutionally mandated; if abuses of those extraordinary procedures impinge on the proper functioning of government, the Senate has an obligation to reconsider the means by which these maneuvers may be employed. And in fact both of those legislative tools are now being used in unprecedented and harmful ways (harmful not because of the policies they may resist but because they have devolved from the legitimate purpose of forcing serious deliberation on important matters to being simply a means of throwing sand in the gears for narrow, trivial, personal, or partisan purposes).
Although the filibuster has been used in support of nefarious causes (the attempt to block civil rights legislation being the most recognized example), it is not in itself hostile to the aims of democracy. In fact, it's just the opposite. The entire constitutional structure--no "head of government," equal branches, equal houses within the legislative branch, powers reserved to states and local governments, authority withheld from the federal government, the many and duplicative steps required to move one's desires from idea to law--is designed to slow the workings of the system, to ensure that major changes in the state-citizen relationship can move forward only after careful and deliberative process, to protect against the whims or ideologies of a temporary majority or (as Frank Capra demonstrated in Mr. Smith Goes to Washington) the illegitimate maneuverings of the self-serving.
So defending the role of the filibuster is not difficult; it serves a purpose that fits well within the scheme of a government intended to protect (which is why, in our governmental structure, we are citizens, not subjects). But....
The filibuster has become not a last defense against dramatic change, or to forestall an injustice, but a common weapon in legislative debate, effectively requiring a super-majority to enact almost any legislation at all. The use of the once-rare filibuster, employed perhaps half a dozen times in an entire two-year session of Congress, has increased nearly ninefold in recent decades, threefold just since the early 1990s, and while President Obama and Democratic Congressional leaders feign outrage over the practice (or maybe actually are outraged), the tactics used by Republicans now to block Democratic initiatives were used by the Democrats when George W. Bush was President and Republicans controlled Congress. The problem is partisanship, the abuse is bipartisan and the solutions must be non-partisan.
As a general rule, I think it a wiser policy to move slowly than to act quickly, especially when the nation's laws are being considered. Better to be temperate than to be "efficient." But just as the Constitution constrains government action, it also empowers the people, through their representatives, to make decisions and act in the national interest. Self-government does not preclude majority rule so long as the rights of a minority are not put at risk. To require the votes of 60 percent of the Senate to move forward on virtually anything at all, even if benign, is to turn the very concept of democracy on its head. We are not a pure democracy--we have a limited, constrained, mediated democracy--but it is a democracy nonetheless .
One of the problems is that senators no longer need to put themselves on the line, risking the enmity of their colleagues and constituents, to "filibuster." It is one thing to feel so strongly about an issue that one will brave the wrath of many to stand for a perceived principle of great importance. The Senate, in the name of efficiency, made an important change in its procedures. With a new managerial tool called "tracking," leaders were empowered to keep several items moving simultaneously so a filibuster against one item would not bring the entire Senate to a standstill. It was a clever idea and served the purpose of allowing the legislature to function while allowing principled opponents to forestall action in a particular bill. But as a corollary, since a filibuster would no longer impede the Senate from moving forward, it was decided that it would be sufficient for a senator to merely threaten a filibuster to yank an item from the agenda. No longer was there any need to incur wrath nor to make a sacrifice (previous filibusters may have required a senator to speak non-stop for hours on end, to the point of starvation and exhaustion, thereby demonstrating the strength of their feelings). A filibuster no longer demanded the existence of an overriding principle to be defended nor the willingness of its champion to withstand slings and arrows in defense of a cause. Thus the filibusters have become routine, common, another weapon in the never-ending partisan warfare that has overtaken American politics.