A year ago, Barack Obama was elected to bring change to America. But his efforts to transform Washington are being stymied by one of the capital's oldest of political traditions: the Senate filibuster. Ten months into Obama's presidency, Democrats have passed just one major piece of legislation, February's stimulus package.

But from judicial and executive branch nominations to health care, labor and financial reform, the very threat of the filibuster and other obstructionist techniques by Senate Republicans has stopped President Obama's ambitious political agenda in its tracks.

Reforming the way Washington operates is hardly the sexiest of topics, but from a policy and even a political perspective, there are few more important issues on which Democrats should be focusing their energy. Quite simply, the filibuster has become the single tool that is undercutting everything Obama and the Democrats were elected to achieve.

Both parties have historically used the filibuster, but its overuse by modern Republicans stands at outrageous proportions. Not only has the number of filibusters increased dramatically -- from never more than seven a year in the 1960s to a record 137 in the last Congress -- so, too, has their banality.

For example, this month the Senate unanimously passed an extension of unemployment benefits. It took the breaking of three filibusters and five weeks of debate to pass the bill while, at the same time, 200,000 Americans lost their benefits. Even pettier is the GOP's repeated use of holds. Thomas Shannon, the president's nominee to be ambassador to Brazil, is a career Foreign Service officer and served in the Bush administration. But that has not stopped two Republican senators from holding up his nomination, for unknown reasons.

On health care, Republicans have made clear they will use a filibuster to prevent the Senate from even voting on a legislative solution. So instead of trying to create the best health care bill possible, Democrats are reduced to crafting legislation geared toward overcoming the obstructionist techniques of a minority of senators. Though Democrats theoretically have enough votes to break a filibuster, independent Connecticut Sen. Joe Lieberman has said he will side with Republicans in blocking consideration by the Senate of a bill that features a public option. He may be joined by recalcitrant red-state Democrats fearful of the political fallout. It's hard to imagine that the Founding Fathers intended to create a legislative body in which the whims of a single member could so directly affect the life of the nation.

In effect, majority rule in the Senate has been supplanted by undemocratic, supermajority rule. The filibuster has become a tool to block not just bad legislation but all legislation; it has become so endemic that it is now an institutionalized way of doing business, casting its shadow over everything the Senate does.

Solutions to the filibuster problem exist; what is lacking is political will. One proposal -- offered, ironically, by Lieberman -- would require 60 votes on the first motion to end debate but progressively draw the number down to 51 on subsequent votes. The number of votes needed to end a filibuster could be decreased, as was done in 1975, when it was dropped from 67 to 60. Rules requiring unanimous consent could be modified to require a higher number of objections to stop Senate proceedings.

Or the Senate could go back to the past by requiring that members actually debate a bill on the floor, as opposed to simply threatening to filibuster and thus preventing a vote. Considering that only a simple majority is needed to change the rules governing filibusters, the reform possibilities are limitless.

Yet while Democrats rail against the GOP's use of the filibuster, they seem wary of doing anything about it -- no doubt fearful that when they are out of power, they will be unable to wield the filibuster against Republican proposals. Yet the longer they allow the GOP to thwart their agenda, the greater the likelihood that Democrats will soon find themselves in the minority.

The GOP's continued misuse of the filibuster represents the single greatest threat to the Democratic Party's progressive agenda and its political future. Biting the bullet on modifying its use will not be easy, but the longer Democrats empower Republicans by accepting institutionalized obstructionism as the status quo, the more likely they are to confirm the worst suspicions of their opponents and disappoint their most ardent supporters.

Both Obama and Senate Democrats need to make solving this problem a key element of their near-term agenda, either by raising the profile of GOP obstructionism or by forcing actual changes. Obama was elected to end the dysfunction that defines Washington; ending the undemocratic use of the filibuster must be the first step.