Tomorrow, the Supreme Court will hear oral arguments about President Trump’s power to impose sweeping tariffs. “Marketplace” host Kai Ryssdal spoke to Blake Emerson, a professor of law and political science at UCLA, to discuss the legal questions at hand and their economic stakes. The following is an edited transcript of their conversation.

Kai Ryssdal: For those of us who are not lawyers, what is the main question at issue in this case?

Blake Emerson: The big question is whether the Trump administration has the power to impose tariffs on imported foreign goods under the International Emergency Economic Powers Act. That statute empowers the president to regulate the importation of foreign goods in times of a national emergency. So, the big question right now is, does the authority to, quote, regulate include the authority to impose a tariff?

Ryssdal: There is this thing called the major questions doctrine, which, as I understand it, again, not a lawyer, is a big deal in this case. Help us understand.

Emerson: For sure, the major questions doctrine is a very important rule of administrative law that the Supreme Court has deployed really energetically in the past several years, particularly during the Biden administration. And what the major questions doctrine says is that if the President wants to do something really big, if he wants to issue a policy of what the court calls vast economic and political significance, there must be explicit authority in the statute for that exercise of power. And so now the question is, does that same principle apply to Trump's efforts to impose tariffs? And one might think that it would, right, because these tariffs are massive. They have huge economic effects, and the statute does not use the word tariffs or duties or tax. It uses the word regulate. So, you might think that the major questions doctrine would prevent what the Trump administration is trying to do here. But it's far from certain that that's going to be the result that the Supreme Court will reach, even though that is the result that the Federal Circuit reached in the opinion below.

Ryssdal: Am I overstating things if I say that this, this case really is about the way this economy is run? You and I have talked a lot of times about administrative law and how that's the way the economy is run, but this is kind of the same deal, right? This is how the economy is controlled.

Emerson: Absolutely, I think if you look at what the Trump administration is trying to do, it's trying to develop a new form of presidency-centered economic regulation. What's troubling, or at least novel about that is that there's a risk in this case that the Trump administration, if it gets the blessing of the Supreme Court, may create a kind of end run around the separation of powers. Because in this case, we're dealing with the power to tax, and the power to tax is vested explicitly by the Constitution in Congress, and if the president ends up having a kind of free-standing power to impose taxes, he'll be able to regulate through that mechanism. Because we often say that you can do most of the same things you could do with a regulation through a tax. Instead of saying you can't do this, you impose a tax of a large enough size that make it prohibitively expensive to do that same thing.

Ryssdal: I was about to say one tries to guess what the Supreme Court is going to do at the risk of one's reputation, but this court does have history the past year or so of siding with the President. Spitball this one for me. What do you think happens? Because, as you said a minute ago, they've used the major questions doctrine to strike down things that are far less economically significant than this. So, what do you think happens this time?

Emerson: It's a good question. It's always tricky to guess, but there is a significant likelihood that the court may uphold the tariffs. And there are some plausible legal arguments that this case is different. First, to the extent that these tariffs implicate the President's foreign policy powers, then there's an argument that Justice Kavanaugh at one point made that well, the major questions doctrine shouldn't apply in those cases because of the President's constitutional powers. I think the other factor that's worth keeping in mind, though, is the Supreme Court's general interest in an expansive conception of the presidency, especially where it concerns the Trump administration. What we've seen over the past six months is that the Trump administration has had an astonishing winning streak, and so I would not be surprised if the court ultimately concludes that these tariffs are permissible, especially because they may hesitate before stepping into a policy matter of such gravity.

Ryssdal: I buy that analysis, but, says the non-lawyer in the conversation, we do remember that the court has been skittish about messing with the economy. I point you to, I forget the name of the case, but where they carved out that exception for the Federal Reserve when talking about the executive's ability to fire heads of agencies. So clearly the court is aware of economic mayhem that may result.

Emerson: That's right, yeah, so the Supreme Court has signaled that it at least has doubts about the President's ability to remove members of the Federal Reserve Board, even though it seems to be okay with the president firing and controlling the heads of other agencies like the National Labor Relations Board. So, it's true that the court seems to have some limits. I think the best analysis here, though, is not that the court wants to give the president complete carte blanche authority to do whatever he likes. What the court wants to do is to make sure that it retains its authority. So, you know, there's a lot of talk these days about the unitary executive, this idea that the President has all of the power over the executive branch, and Trump has exercised that theory extremely energetically. But at the same time, what we've seen is the Supreme Court is retaining the authority to constrain or else to bless those exercises of power. So, what I'm seeing emerging is not really a unitary executive, but a binary executive, where the President and the court together become the apex of federal government.