It appears that Tuesday’s results have resulted in a bit of a milestone in the push to fix our broken Senate: Half of the 2013 Senate now supports some form of filibuster reform.

The train seems to be moving forward.

The math is convoluted, but it gets you there. In 2011, the Senate voted on a proposal to force Senators to employ a “talking filibuster,” requiring a more public role in filibustering that might dissuade the practice. It failed, but 39 Senators who will be in office next year voted Yes. Senators who did not vote Yes — such as John Kerry and Daniel Inouye — have come out for reforms. Harry Reid made news this week by saying the time for reform has arrived. That’s 42 Senators.

On Tuesday, seven Dems were elected to the Senate, all of whom have pledged to back reform. So does newly elected independent Angus King. That’s 50.

It’s unclear what proposals these Senators will coalesce behind. Senator Jeff Merkley, who is prodding colleagues behind the scenes, has proposed reforms that, among other things, would force the aforementioned “talking filibuster.” Harry Reid has voiced support for nixing the “motion to proceed”; you’d no longer need 60 votes just to debate a bill. That would force debate into the light of day, rather than allowing Senators to procedurally execute bills in the dark of night.

There’s been some debate over how filibuster reform would get accomplished. It’s possible a bare majority can change the Senate rules at the start of a session.

But beyond the question of what package of reforms Senators might unite behind, and beyond the arcana of how reform would get done, it is significant that half the incoming Senate now agrees that the status quo in the Upper Chamber is unacceptable.

It’s unclear what this means for Obama’s second term agenda. Even if the filibuster is reformed, the GOP still controls the House. But as Steve Benen notes, the immediate problem facing us is that GOP obstructionism has rendered the Senate almost entirely dysfunctional. It has become a legislative body that simply no longer functions by majority rule. The filibuster has become a tool that the minority can use to paralyze government at its most basic functional level, purely for partisan ends, in order to render the majority a failure, no matter what the nature of the majority’s legislative aims.

That’s unsustainable. And we’re very close to the point where a majority of the Senators themselves agree.