President Obama says that, when it comes to congressional action on gun-safety legislation, “This time must be different.”

No longer should partisan obstruction be allowed to block congressional action on sensible reforms that are favored by great majority of Americans, the president says.

He’s right.

But Americans who want sensible gun laws need to recognize that to address mass violence the Senate must, when it convenes January 22, begin the process by addressing abuses of the filibuster power.

Even then, it won't be easy. There are plenty of shaky Democrats.

But those Democrats won't be put to the test unless there is a vote. And there is unlikely to be a vote on any major piece of gun-safety legislation without reform of the filibuster.

Historically intended to guarantee debate, the filibuster has been reinterpreted in recent years as a tool to preempt debate. This has created what Senators Jeff Merkley, D-Oregon, and Elizabeth Warren, D-Massachusetts, correctly characterize as a “culture of obstruction” in the Senate. Merkley, Warren and other Democratic senators have the power to rewrite the chamber’s rules at the opening of the new session, a power they must exercise this coming week if this session is to be different from the last—which have seen the highest number of filibusters in congressional history.

Every evidence suggests, in the absence of the reforms proposed by Merkley and Warren, any debate about meaningful gun-safety legislation will be preempted, any action obstructed.

Senate Minority Leader Mitch McConnell, R-Kentucky, and his caucus currently control just forty-five of 100 seats in the chamber. They actually lost ground in the 2012 elections. But unless filibuster rules are reformed, they will be able to block action on the measures President Obama and Vice President Biden have proposed in response to the shootings in Newtown, Connecticut.

The key phrase there is “block action.” In recent years, the filibuster has not in any meaningful sense been used to give the minority a chance to air its views, to encourage real debate and where necessary to extend debate or to allow convincing arguments to be made. It has been used to block debate by preventing consideration of even popular proposals.

The filibuster, as it is currently defined, is not a tool for deliberation. It is a tool for preventing deliberation. And it will prevent deliberation on gun-safety legislation.

That’s a big deal, because Senate action on gun-safety legislation will provide the impetus for House action. It’s no secret that House Speaker John Boehner, R-Ohio, and his caucus are under the sway of the National Rifle Association, which has become a prime source of messaging and funding for Republican campaigns as it has abandoned most pretenses toward bipartisanship. Boehner and Majority Leader Eric Cantor, R-Virginia, are not about to allow a vote on legislation the NRA has sworn to stop unless they are forced to do so.

It is true that President Obama has a bully pulpit, and the remnants of a campaign apparatus, that can move public opinion. And public opinion is a factor when issues are brought to a vote; it is imaginable that a number of Northeastern Republicans (and some others from across the country) might—as Republicans in the New York legislature recently did—back moderate gun-safety legislation. But for that to happen, the legislation has to be brought up for a House vote.

That’s far more likely to happen if the Senate has passed gun-safety legislation. It’s not just a matter of strengthening the popular argument for House action; there are practical tools—including the budget process and conference committees—for increasing the pressure on the House to act.

And this returns us to the filibuster.

For the Senate to act on gun safety, the essential first step is to end the abuse of the filibuster. That will require specific action to restore, in the words of Merkley and Warren, “a full talking filibuster.”

This is an essential understanding: Reform must restore the filibuster as it was historically understood, and as Americans know if from films such as Jimmy Stewart’s Mr. Smith Goes to Washington.

“Other proposals out there don’t go far enough, and won’t change the culture of obstruction that paralyzes the Senate,” say Merkley, Warren and New Mexico Senator Tom Udall.

A paralyzed Senate will not debate or vote on the gun-safety legislation that is required to assure that” “This time is different.”

For more on the NRA's (non-)role in the gun control debate, read John Nichols's media critique.