In filibuster news today, Common Cause and a handful of Democratic members of the House have filed a federal lawsuit, alleging that the filibuster is unconstitutional. I support Senate reform, and I don’t like the 60-vote Senate that Republicans instituted in 2009 — but Common Cause and its allies are wrong about the constitutional status of the filibuster.

I’ll start with the bottom line: The Constitution is very specific that Congress generally can govern itself however it likes, because “each house may determine the rule of its proceedings.” That’s Article I, Section 5, and there’s really no getting around it.

The Common Cause group argues that constitutional provisions are not unlimited. That’s true, but they are wrong that Senate Rule 22, the rule that governs filibusters and cloture, conflicts with other constitutional provisions.

For example: The plaintiffs argue that the Constitution specifies certain votes require Senate supermajorities, and therefore the supermajority for cloture conflicts with a constitutional presumption that all other votes will be by majority rule. That logic just doesn’t make sense.

The simplest way to reconcile the requirement of certain supermajorities with the instruction that the Senate gets to set its own rules is to say that the Senate sets its own rules except for where the Constitution specifies otherwise. Thus the Senate does not have the option of not keeping a journal of its proceedings, but it does have the option of whether to make all votes recorded votes; it must use a supermajority for passage of treaties but can choose to handle floor procedure however it sees fit.

Looking at the larger picture, the Common Cause group makes much of majority rule. The truth is that filibusters (and their much-despised cousin, holds) are only one way that the Senate, and that Congress in general, subverts simple-majority rule. The majority party can prevent popular items from coming to a vote by killing them in committee, by simply refusing to offer them on the floor or by blocking amendments from being offered.

It makes little sense to say that the Constitution requires a simple majority to bring something to a vote on the Senate floor but permits a well-positioned minority to block it before that point.

To put it another way, eliminating the filibuster wouldn’t achieve majority rule in the Senate; it would achieve what the House has — majority-party rule. That’s a very different thing. And it’s extremely difficult to believe that the Constitution mandated majority-party rule, given that parties didn’t even exist yet.

The plaintiffs begin by asserting that “Nothing is more fundamental to a democratically elected legislative body than the principle of majority rule.” That, too, is not true. We use majority decision for all sorts of good reasons, but what’s really fundamental are ideas of representation and democracy, and neither of them is strictly dependent on majority rule; to the contrary, virtually everything about Madisonian democracy leads us to be suspicious of simple-majority rule — beginning with the existence of the Senate in the first place. Bicameralism is all about undermining simple-majority rule.

None of this means that the filibuster should stay as it is. I think a strict 60-vote Senate is dysfunctional, and while I’d be happiest keeping the current rule and restoring the old norms, realistically that’s not going to happen, and in my view a new set of rules is needed. But none of that has anything to do with whether the Senate should be allowed to govern itself. The current Senate rules are absolutely constitutional, and this Common Cause lawsuit is just a distraction from the real work of figuring out some rules that can make the Senate work better.