With an extremely narrow majority in the Senate, Democrats are trying to pass President Biden’s $1.9 trillion covid-19 relief package through budget reconciliation. That’s a procedural shortcut that allows legislation to pass the Senate with a simple majority rather than the 60 votes usually needed to end debate. But only certain kinds of legislation can be passed through reconciliation, and a relatively obscure Senate official — the parliamentarian — is poised to play a key role in deciding whether the bill’s provisions qualify.

We asked Jonathan S. Gould, a University of California at Berkeley law professor who has written about the role of the parliamentarian, about the history of the office, how parliamentarians make their decisions and the office’s future in an age of congressional polarization.

Why is the Senate parliamentarian making headlines?

The power of the parliamentarian in the new Congress results from the intersection of the Democrats’ legislative ambition and Senate rules. Under Senate Rule XXII, a three-fifths vote is required to end debate on ordinary legislation. But in our partisan age, it looks unlikely that the Biden administration will get 60 votes for its legislative priorities. So Democrats will be legislating through reconciliation, an obscure feature of the 1974 Congressional Budget Act (CBA).

But not everything can be done through that process. The Byrd rule, a provision added to the CBA and named after the late Sen. Robert Byrd, says what can and can’t be done through reconciliation. Without going into detail about the rule, here’s the key point: Reconciliation can only be used if the provision is genuinely related to the budget. It’s the parliamentarian’s job to interpret the Byrd rule, the same way a federal judge might interpret the First Amendment. For the covid relief bill, for example, the parliamentarian will have to decide whether, under the Byrd rule, reconciliation can be used to raise the minimum wage.

How long has the office been around?

The House parliamentarian dates to 1927 and the Senate parliamentarian to 1935. During the New Deal, the Senate aspired to increase its capacity and professionalism. Given that, as members started spending more time in committees and less time on the floor, the parliamentarian ended up developing a unique knowledge of parliamentary procedure that allowed them to oversee action on the floor. It’s an office with a strong institutional culture, in which parliamentarians and their staff typically serve long terms.

How do parliamentarians make their decisions?

Parliamentarians make decisions based on Senate rules and decades of precedent. Their formal role is on the floor. For example, when the minority party raises a point of order objecting to something the majority party is trying to do, the chair — a member of the majority — has to rule on that point of order. The parliamentarian is the one whispering in the chair’s ear, telling them what the relevant rule is and how they should rule. The parliamentarian acts a lot like a judge, even though the final decision is the chair’s.

Parliamentarians also informally advise both parties as members draft or consider bills, explaining how the rules apply. They also preside over informal adjudications of Byrd-rule issues before a reconciliation bill gets to the floor. This process isn’t open to the public, but it involves a hearing that falls somewhere between fully informal and fully formal.

Can these decisions be appealed?

When a parliamentarian gives informal advice, that’s not binding, so there’s no appeal. In the formal setting, the parliamentarian advises the chair and the chair issues a ruling. That ruling can be appealed and overruled by a simple Senate majority. That’s how Democrats eliminated the 60-vote requirement for lower-court and executive-branch nominees in 2013, and how Republicans did the same for the Supreme Court in 2017.

How have parliamentarians escaped the polarization that has otherwise gripped Congress?

It’s been difficult, but they have done a few key things to maintain a reputation for neutrality. For one, the office has adopted methods that emulate what we see from judges and hesitate even more than the Supreme Court to overrule precedent. This allows them to set consistent expectations and apply the same rules whether Democrats or Republicans are in power, which helps ensure their decisions are perceived as fair.

The parliamentarians also build deep relationships on both sides of the aisle. And the parliamentarians have unique knowledge about the rules of Congress and volumes of precedent. If a majority were to get rid of the parliamentarian, it’s not clear whom they could hire as a qualified replacement.

Will the parliamentarian be in the hot seat more as polarization increases?

The parliamentarian has been in the hot seat before. In 2001, for example, Republicans removed Senate Parliamentarian Robert Dove, whom they themselves had appointed, over a dispute over what could be done through reconciliation. But continued polarization will likely put ever more pressure on the parliamentarian, as long as the filibuster remains. When it is virtually impossible to get 60 votes for major legislation, more will happen through reconciliation, which in turn means more disputes over the scope of reconciliation.

Is the office likely to remain nonpartisan going forward?

I see two possibilities. If the Senate eliminates the filibuster, that would take a lot of pressure off the parliamentarians, because they would no longer be in the uncomfortable position of saying no to majorities and protecting minorities. But if Democrats and Republicans both continue to have to use reconciliation to enact major legislation, the parliamentarians will continue to police the boundaries of that process and may find themselves marginalized or even fired. But they are attuned to that risk.

When push comes to shove, if a parliamentarian has to choose between bending rules to the majority will or blowing up an office that’s been an institutional pillar for decades, they might do the former rather than the latter. But they certainly hope it won’t come to that.

Nikita Lalwani is a 2020 graduate of Yale Law School.