Core issue

The Senate Filibuster is well known (skipping the background here) and its primary workaround for legislation, Reconciliation bills, which were originally solely for purpose of making adjustments to balance the budget.

Conventionally, the Filibuster protects the minority from the actions of a slim majority. And therefore Reconciliation, which allows sidestepping the Filibuster for many purposes, breaks that mechanism, and because a simple majority is sufficient, there is decreased incentive to negotiate, and partisanship is the result.

I propose a different framing: Reconciliation encourages partisanship not simply because a simple majority is sufficient, but because the majority coalition in favor of passing the reconciliation bill will be composed of (nearly) only the majority party, rather than allowing other coalitions to form. There are many questions before any given session of congress, and it is only natural that a lawmaker would have opinions on certain pieces of legislation they deem important that don't align with their coalitions on other legislation. And those coalitions might align little with the parties of its members, yet still be a majority (or minority). The coalitions for any particular legislative priority do not need to align with an external structure like a political party.

But when the Reconciliation mechanism becomes a standard method of passing legislation, and they become omnibus bills bundling many different priorities together, then there become many reasons both to vote in favor of the bill (so many important items, including those from committees one is a member of) but also so many reasons to vote against (so many problematic items), with little serious means to negotiate the issues, as serious negotiation would hold up all the provisions in the bill. Negotiation can still happen before the committee reports to the floor, but engagement and leverage are entirely different, as the vote of a (majority party) extra-committee member is given by default in the reconciliation process (they need to vote in favor of the package so their own committees' provisions pass!), they need something else to bargain with.

As such, Omnibus bills are not necessarily attractive to even members of the party that passes it. For most provisions (we'll get to committees soon), lawmakers on the majority party are expected to simply assent, and even those who do object limit themselves to a couple of provisions. This enforces partisanship for legislation that in another context, members of the majority party might have disagreed with, members of the minority might have agreed to, and in any case they'd be in a better position to negotiate over the details of the bill (itself a process that can lead to a majority of lawmakers in favor).

But Reconciliation is used to push through highly controversial and partisan legislation, and once it becomes a tool (which consumes significant senate resources), it ends up bundled with other extraneous legislation, even if it wouldn't be hyper-partisan if brought to the floor, because it's simpler to deal only with the question "what do the majority of committee members think".

Suppose the following possibilities:

1. Cloture requires 60 votes, except for (some, Reconciliation) Omnibus bills, which has a simple majority path.
2. Cloture requires only 50 votes (or senate legislation is not otherwise filibuster-able).
3. Cloture requires 60 votes, but reconciliation is not exempted from the Filibuster.

The worst of these options is the first, which is effectively what we have today (inasmuch as reconciliation bills are exempted, though they are not the only type of omnibus bill). It is the only option that requires a primary allegiance (to a party) to dominate any other priority, because (nearly) the whole party must agree for the party to pass in a reconciliation bill, which is where so much happens. Option 2 also enables party line legislation, but it doesn't prevent a non-partisan majority from forming, while option 1 helps prevent coalitions distinct from the parties from forming.

(The implicit assumption is that the Reconciliation being exempt from the Filibuster will result in bundling. Once a reconciliation bill takes up time, there is always the incentive to add other extraneous legislation to the fast path, and as that becomes accepted, it happens more. However, my main point is about bundling, and it's easiest to reason about the current situation where bundling is common in reconciliation bills.)

But it is not simply polarization that is the problem, polarization is one product of lack of agency and accountability that this structure strongly encourages.

In other contexts, the Filibuster was removed in partisan play (e.g. confirming Judges). The motivation is clearly partisan, and the change means that such roll-calls can be partisan (and are therefore lack an incentive to be more broadly palatable), and has been decried as such. But the wholesale bundling of provisions doesn't just bypass the Filibuster, it bypasses the Filibuster with an all or nothing vote on effectively many bills at once preventing other senate-wide (as opposed to committee-wide) coalitions from forming.

What else happens when the floor vote stops being a meaningful signal of what senators themselves think?

Who gains?

Reconciliation means serious boundaries on what input a senator has on legislation. But committees are alive and well, and therefore those with power over committees retain the most initiative.

With ordinary legislation, committees consider legislation, and report the bill to the floor, where it will be voted on. This gives committees the primary affirmative say in what priorities to consider, and what should be done about it, while other senators have leverage via veto: they can refuse to vote for the bill, or refuse to vote for it without amendment. This second part, amendment, and specifically the debate that is necessary for it, is also the mechanism that is used for the Filibuster. The floor vote is also a feedback signal to committees: committees spend time on priorities and solutions that they (or the chair) think they can convince others about, and build a coalition. And as noted, the coalition in favor of a bill may or may not be partisan. Either way, you need to build that coalition, because even if it will be the majority party that is in favor of addressing an issue, that doesn't mean they're in agreement on how to do it either.

In Reconciliation, while the committee retains its position, it is a near given that the legislation from Committee will make it into the final bill, and pass final vote. That doesn't just mean the minority party gets no say, it means most members of majority party also get no say.

(Amendments exist, but the vote-a-rama, whether it's effectively a vote to change a provision that is otherwise guaranteed passage - rather than a vote whether to accept a provision, or because leadership can fill up the time slots, or there not being time and focus for each provision, or lawmakers incentivized to use this time for point scoring instead of substantive amendments. Ultimately provisions do not receive individual consideration. I acknowledge insufficient understanding of this process, so I may be missing something here).

Lawmakers do retain their vote for legislation considered by their committee, but (in addition to losing their say on legislation outside their committee) the committee itself is no longer guided by floor feedback, though dealmaking may be alive and well.

Those who gain the most from the loss of this feedback mechanism is leadership, who control the agenda, and have more freedom in setting that agenda. This also gives them more bargaining power in dealmaking.

Reframing

Omnibus bills mean that the senate will have an all or nothing vote on all provisions, removing an essential part of the institution (insofar as Reconciliation / Filibuster bills are concerned). This results in little need for coalition building with other lawmakers, which partisanship is downstream of.

Put differently, provision bundling results in the few (a majority on committee) wielding power over the many (though who "the few" are is different with each provision). Not as a veto, as it is with a Filibuster, but the ability of committees to actively legislate (within the limitations of the Reconciliation process). To pass committee, you need a majority, quite possibly composed of the majority party, but outside of committee, you'll have a majority not on the merits of your provision, but on the merit of passing any and all provisions.

It also means that senators are siloed: much power where they are, less input over the collective congress. Less input not only because they are one person, but because they cannot even join with others in coalition - you need to convince others not only that you're right, but that it's worth torpedoing the whole omnibus bill over it.

There's also less ability to have substantive discussion of legislation and whether your senator voted for or against: your representative lawmakers' final vote on a reconciliation package is a statement of party loyalty (or that there were a few overridingly important provisions in the bill, or that they wanted their own provisions to pass), but thereby tells us little about what they think of any specific issue or provision in the package.

From this perspective, we should consider: how can we stop the floor vote from being an all-or-nothing vote? What rule changes would enable provisions in reconciliation to receive consideration on the floor individually (or in small groups), such that lawmakers outside committee have a say?

A vote on each committee's work is obviously too coarse a measure, and allowing any senator to propose an arbitrary breakup of provisions for a vote is too impractical with existing Reconciliation to possibly be adopted. We're looking for a change that promotes proper consideration of bills on the floor, without derailing the existing process so much that no one can agree to accept it.

I don't know exactly what the solution would be, and I don't know enough about the working of congress to have an idea of what would work here. But I feel an answer might be found in this direction.

Filibuster reform proposals

Recently, Senators have proposed Filibuster reform (Opinion | Sens. Merkley and Daines offer their bipartisan plan for Senate reform - The Washington Post), bypassing the filibuster when there is sufficient support from bipartisan leadership and bipartisan committee support, and shortening the post-cloture (debate) period. This prevents individuals from using the filibuster as leverage. I will add that it also doesn't grant too much power to committee heads, and those outside the committee can still choose to vote against it.

This proposal has received praise (A Worthwhile Package of Senate Reforms | National Review) for not being a partisan vehicle:

Unlike moves to eliminate the filibuster, and most ideas for constraining it, the incentive this creates is not for party discipline but for cross-partisan bargaining.

That distinction is essential. I think that every reform of Congress should be subjected to a simple question: Is this idea trying to make more legislation happen by making cross-partisan bargaining more likely, or is it trying to make more legislation happen by making cross-partisan bargaining less necessary? The first would be a way to help Congress perform its most essential function, facilitating negotiation among the factions that compose our politics. The second would be a way around that most essential function.

I agree. In light of the above framing about the structure of power, I note that although significant say is given to leadership in this process (if they don't agree, the bill is blocked), leadership effectively has this power anyway by simply choosing to not schedule a vote (to report a bill, or vote on it on the floor) although these can sometimes be worked around. On the other hand, bipartisan members of the committee must also agree to pass the bill, so it's actually giving some veto leverage to the members of the committee.

And although the net is that the committee has lots of say in whether to use the expedited process, other senate members will have their say at the floor vote, preserving the feedback mechanism. So while committee members gain some veto power, it's not much more veto power than the committee as a whole has today.

Nevertheless, it's not clear how much more coalition building this would encourage, because specific members (leadership), retain veto power over this expedited process. Still, any progress is progress, and so long as the goal and incentives are to improve (rather than quiet the voices of change), it paves the way to further improvements that would be unthinkable in a more dysfunctional environment.

Because of the relatively high bar to clear under the proposal, I don't expect Reconciliation to stop being a primary legislative vehicle anytime soon. But hopefully we get closer to an unbundling solution.