The most important action the Senate takes in January may not involve any legislation at all. Early next year, when the latest group of senators convene for the first time, the “world’s greatest deliberative body” may finally do something worthy of its nickname: reform the filibuster.

The filibuster long ago shed its association with the principled stand of dedicated outsiders; Mr. Smith left Washington decades ago. Rather, the opposition parties of the past couple of decades—and especially the Republicans in the Obama era—have transformed the filibuster from a weapon deployed in extraordinary circumstances into a routine part of Senate business. In recent years, it’s become the rule, rather than the exception, that the majority has to muster sixty votes to get anything done. With fifty-three Democrats in the Senate (fifty-five starting next year), this means that Republicans have been able to slow the upper body to a virtual standstill. (George Packer laid out the gory details about Senate dysfunction a few years ago.)

The reform proposal comes from two relative newcomers to the Senate, Jeff Merkley, of Oregon, and Tom Udall, of New Mexico—both Democrats—and it’s fairly simple. Today, senators can “filibuster” simply by announcing that they plan to do so; the Senate then needs sixty votes to move the issue forward. The filibustering senators don’t have to say a word on the Senate floor. The two Democrats’ proposal says that ten senators have to sign a petition to organize any filibuster and then they would have to take the Senate floor and actually talk to maintain their filibuster. The theory behind their idea is that the requirement to stand up and filibuster would create a real deterrent to the profligate use of the tactic. It’s a modest change—filibusters would still exist—but a useful one.

The controversy offers a small window into the differences between the two parties. In 2005, when Republican Senators were irritated about Democrats’ filibusters of George W. Bush’s judicial nominees, the G.O.P. (which then commanded a majority in the Senate) threatened to impose its own version of filibuster reform. It was called “the nuclear option,” and I wrote about it in the magazine. In short, the “nuclear option” involved invoking a ruling by the President of the Senate (then Dick Cheney) that essentially cut off debate by majority vote, at least on judicial nominations and perhaps other matters.

The parties’ roles were reversed at the time. Then-Senator Joe Biden defended the filibuster, telling me that the Senate was the place where “you can always slow things down and make sure that a minority gets a voice.” Orrin Hatch, the Utah Republican, viewed the tactic with disdain at the time, saying, “By using filibusters on judges, the Democrats have essentially imposed a supermajority requirement, and we are entitled to stop them.”

The denouement of the nuclear-option debate was a revealing one. In short, the Democrats caved. The so-called “Gang of 14,” a bipartisan group of senators, worked out a deal that included a promise by the seven Democrats involved that they would no longer filibuster against Bush’s judicial appointees, except in “extraordinary circumstances.” In practical terms, that meant that the Democrats yielded on virtually all of Bush’s judicial nominations, including that of Samuel A. Alito, Jr., to the Supreme Court.

The question now is whether the Democrats will cave again. Merkley in particular has been pushing the issue of filibuster reform for some time, but Harry Reid, the Senate Majority Leader, stymied the effort in 2011. Reid has publicly changed course this time, however, saying earlier this year, “These two young, fine senators said it was time to change the rules of the Senate, and we didn’t. They were right. The rest of us were wrong, or most of us, anyway. What a shame.”

Indeed, it was. But it remains to be seen how serious Reid is about filibuster reform. Senate leaders tend to be institutional conservatives, who worry, with some justification, that their party will be in the minority some day. But Republican obstruction has become such an obstacle to legislative progress that the risk seems worth taking.

This is especially true because judicial nominations are likely to be more of a focus for President Obama in his second term. With the House in Republican hands for the foreseeable future, it is unlikely that major legislation will pass both bodies of Congress. But the Senate has a constitutional obligation to take up Obama’s judicial nominees—and the fights over them are likely to be fierce. If Reid and his fellow Democrats give up on filibuster reform, they will likely doom the President’s second-term legacy before he even has a chance to write it.

Photograph by Luke Sharrett/The New York Times/Redux.