Not wishing to take responsibility for making hard choices, members of Congress (particularly when the president is of their party) have long been happy to enact vague legislation at best and to leave big decisions to the executive and judicial branches. Over time, as this habit has hardened, they have lost the knack and the muscle memory for legislating.

In fact, although everyone agrees Congress is broken, it has eschewed its dominant role for so long that even reformers disagree about what it is that Congress is failing to do in the first place — and what purpose institutional reform should serve.

Is Congress’s purpose to implement the agenda of the majority party most effectively, or is its purpose to compel and enable accommodations in a divided country? Today’s Congress does neither very well. But which failure is a bug and which is a feature?

Those two visions of Congress’s purpose (which the political scientist Daniel Stid labels “Wilsonian” and “Madisonian,” respectively) generally point in opposite directions when it comes to strengthening Congress, but they are too often confounded. The Wilsonian vision would have Congress function more like a European parliament, with stronger centralized leadership and fewer choke points and protections of minority prerogatives. It would enable the party that won a majority of seats to enact its agenda and see what voters make of it in the next election.

The Madisonian vision would recover the purpose of Congress in our larger constitutional system but would mean slow going, greater cacophony, less centralization and more opportunities for coalitions of strange bedfellows to form. It would have Congress serve as an arena for continuing bargaining and compromise, on the premise that greater social peace is better for the country than either party’s bright ideas.

A more parliamentary Congress has been the dream of progressive reformers for more than a century, but it is a poor fit not only for a system of divided powers but also for a polarized society. We need Congress to pursue and drive accommodations — in fact, as the political scientist Philip Wallach has recently argued, Congress is really the only institution in our system of government that could do that.

Reforms rooted in that vision would need to focus especially on the budget process, which has come to dominate and distort Congress’s work. Making that process more like legislative work (divided into small, discrete, concrete steps that call for bargaining over particulars) and less like executive work (consolidated into a single, large decision that calls for unity around abstractions) would advance the Madisonian ideal of Congress and could mean rethinking elements of the committee system, the work of “scorekeepers” (like the Congressional Budget Office), the relationship between leadership and backbenchers, even the distinction between authorizing and appropriating that now too often separates policy priorities from budgeting.