The third possibility is the one I think that is on everyone’s mind, and in some ways probably the most likely outcome of the case. That ruling would say Abood is wrong, we overturn it: It is unconstitutional in the public sector to require a public employee to pay dues to the union, even when those dues are used only for collective bargaining purposes.

That ruling would convert all public sector employment into a kind of right-to-work regime in which no mandatory dues can be required even though the union is required to represent everybody in the bargaining unit. That would be an incredibly sweeping opinion, with dramatic consequences for public sector unions all over the country, including teachers.

This is not just a kind of labor law, labor union issue. Public sector unions are incredibly important to our politics. They are a primary supporter of the Democratic Party. If you make unconstitutional the dues arrangements in the public sector, you’re really going to — I don’t want to say “cripple,” but hinder dramatically the ability of unions to participate as vibrant political actors.

There’s another thing the court could do. This case all along has been about “mandatory dues.” But in the briefing to the Supreme Court, the Right to Work Committee has now expanded what they’re asking for. So they’re now asking not just that mandatory dues be unconstitutional, but that “exclusive representation” itself be unconstitutional. If that argument is considered by the court and wins, the only kind of unionism you could have in the public sector is “minority” or “members-only” unionism, so that the only people that would be covered by a collective bargaining agreement and represented by the union are those who affirmatively desire to become members.

What do you think that would do to unions’ clout?

The risk is that employers play the unions off each other, and in the long run undermine unionism, but there are also very good and important arguments in favor of minority unionism. So I think it’s hard to predict what it would do to unions’ clout. But most likely it wouldn’t be good.

The statement that Alito made in Knox — that “such free riders arguments … are generally insufficient to overcome First Amendment objections” — do you see that as a tell when it comes to what he and his conservatives colleagues would do on this case?

It’s really risky to try to predict what the Supreme Court will do and it’s even risky to predict what an individual justice will do in a given case. That being said, I think it’s pretty clear that at least one, if not five, members of the court in Knox were signaling an unease with what is fairly settled law in the public sector union context.

There are parallels between the public sector law in Abood and the private sector law that exists in the 1988 case Beck, in terms of drawing a distinction between collective bargaining activities workers can be required to pay for, and political activity that they can’t. If the court moved to the right on public sector dues or fee deduction, would that open a door to a shift in the private sector?

In the private sector, the question [for the Supreme Court] is “what does this federal statute say” — the National Labor Relations Act” — not “what does the Constitution say?” Because under our well-established constitutional law, the Constitution binds the government, not private actors …

What federal labor law now does with respect to the private sector is it just allows private employers and private sector unions to bargain contracts which require the payment of dues. Under constitutional doctrine — what’s known as the “state action” doctrine — that kind of arrangement, where the government says you can bargain a contract which says x, that’s not enough to implicate the Constitution.

No matter what the court says in Harris v. Quinn, that holding should not change the law with respect to the private sector. The only way that Harris v. Quinn changes the law with respect to the private sector is if the court also very fundamentally changes something about the state action doctrine, such that private sector collective bargaining agreements become state action that implicate the Constitution.

The National Right to Work Foundation, which helped bring this case, has described it as an issue about “forcing home-care providers into union ranks.” What do you make of that line of argument?

Number one: There’s never a union unless the majority of the employees themselves affirmatively desire a union. What any state can do, what any private sector employer can do, is give employees a vote about whether or not they want a union — and then the principle of majority rule applies.

Number two: Even under majority rule, nobody can be forced to become a member of a union anywhere in the United States. What people can be required to do is to pay for representational services that they’re provided. The union has to represent everybody who’s in the bargaining unit, even the people who voted no. Along with that obligation on the union comes a requirement that everybody pay dues for the representational activity that the union is statutorily obliged to undertake.

To characterize that as people “being forced into union ranks” seems to miss some important nuance.

In recent years we’ve seen unions, including the Service Employees International Union, which you used to work for, successfully arguing that categories of domestic workers who are excluded from the National Labor Relations Act — and also often from the way workers are thought about in U.S. culture — in fact are at least in part public employees. And thus that they have access to public employee labor law, which in many cases is more pro-union than private sector labor law. How much more room is there for that strategy to advance at the state level, if Harris v. Quinn does not change the existing law?

There are a number of contexts in which state money is paying for people’s labor, and where the work relationships are atomized so it’s not the public schools, it’s not the Department of Motor Vehicles, but it’s where individual workers are providing services dispersed across workplaces and geographies. Home-care work is a good example of that, childcare work is another. This accounts for a significant part of the labor force. These are very important services. It seems to me that there is no reason to exclude these workers from collective bargaining regimes …

States have set up bar associations for lawyers and required lawyers to pay bar dues, and those arrangements have been challenged on just the same grounds [as] Harris v. Quinn … And what the Supreme Court has said is: Look, the state has a real interest in making sure there’s an operative bar in the state; we need that to ensure that the practice of law is ethical and effective and so forth. And if we don’t require everybody to pay dues, nobody will pay dues.

Whether or not you call childcare workers employees of the state, it’s just beyond argument that a state like Illinois has a real interest in running these home-care programs. The interest they have is in making sure people can get care in their homes rather than in institutions. And as part of that state interest, Illinois can make a legitimate decision that they want to interact with the workers as a collective rather than as individuals. And once you make that decision, you have to charge people for it — or you run into this free-rider problem.

You wrote about Mulhall v. UNITE HERE, which also could have had sweeping consequences for union organizing. The decision that ultimately the majority made, that that case was “improvidently granted” – the decision in some sense to punt [rather than ruling] – what, if anything, do you conclude from that about the current court?

If you were to say, what are sort of the two most viable, important sort of mechanisms or strategies for organizing workers into unions today, you would say private organizing agreements of the sort that were challenged in Mulhall, and public sector organizing in home care and childcare of the sort that are challenged in Harris. So the two most important legal strategies for organizing workers into unions in the United States today are both being challenged in the Supreme Court and the Supreme Court agreed to hear challenges of both those strategies. Mulhall was an existential threat to the private sector union movement. Harris an existential threat to the public sector union movement. That’s notable.

It seems, from what we can see publicly, that there was some disagreement about whether the best course or the right course of action was dismissing Mulhall or reaching the merits and ruling essentially for the union in that case — it did not seem that there was majority support for ruling for the respondents in that case.

Does that tell us anything about the current case, or about the merits of that case as a vehicle?

I guess what you might say is that the original grant of certiorari in Mulhall, given all of the very deep procedural problems with the case, might indicate some hostility among some justices to the kind of private organizing agreements that were at stake in the case. At the same time, there weren’t enough votes on the court to reach a holding in that direction on the merits.