The Terms — The Surplus, Plate iv

Exchange creates a surplus, and the surplus is shared between the two who make the trade — but in what proportion? The first plate showed that the price draws the dividing line: everything the buyer keeps above the price is his, everything the seller keeps above his cost is his, and where the price falls decides how much of the joint surplus goes to each. But this only pushes the question back a step. What decides where the price falls? What governs the terms on which the two parties settle, and so the division of the gains between them? The classical economists had shown that trade benefits both sides and had fixed the outer bounds within which any bargain must lie; it was John Stuart Mill who solved the harder problem of where, within those bounds, the terms actually come to rest — and his answer, the doctrine of reciprocal demand, is the general law of how a surplus divides.

Recall the limits the classical analysis had already established. Two parties trade because each can get, through exchange, what would cost it more to make for itself — the principle of comparative advantage, which guarantees that a range of mutually beneficial terms exists. A country that can make cloth cheaply and wine dearly, trading with one whose costs run the other way, will gain from any exchange ratio that lets it get wine for less cloth than it would take to make the wine at home; and the other country gains so long as it gets cloth for less wine than its own cloth would cost. Between those two domestic cost ratios lies a band of terms acceptable to both — but it is a BAND, not a point. At one edge of the band, almost all the gain goes to the first country; at the other edge, almost all goes to the second. The classical result fixed the band and stopped. It established that both parties gain and bounded how the gain could be split, but it was silent on the actual division — silent, that is, on the very question of who walks away with how much of the surplus.¹

1. The classical analysis fixed the limits. Two parties trade because each gets through exchange what would cost it more to make itself — comparative advantage, which guarantees a range of mutually beneficial terms. A country cheap in cloth and dear in wine, trading with one whose costs run opposite, gains from any ratio that gets it wine for less cloth than home production would take; the other gains so long as it gets cloth for less wine than its own would cost. Between the two domestic cost ratios lies a BAND of acceptable terms — not a point. At one edge almost all the gain goes to the first country, at the other to the second. The classical result fixed the band and stopped, silent on the actual division — on who walks away with how much.

Mill filled the silence with a single idea: the terms of trade settle at the ratio where the two parties' demands for each other's goods exactly match. Each country, at any given exchange ratio, wishes to buy a certain quantity of the other's product and to pay for it with a certain quantity of its own. As the terms shift in a country's favor — as it gets more of the other's goods per unit of its own — it wishes to buy more; as they shift against it, less. The terms of trade are settled, Mill argued, at precisely the ratio where the amount each country wants of the other's goods equals the amount the other is willing to supply in return — where the two reciprocal demands are in balance, so that the value of what each sends out equals the value of what it takes in. This is RECIPROCAL DEMAND: not supply and cost alone, as in the classical picture, but the mutual pull of each side's desire for what the other makes, the two demands meeting and fixing the rate of exchange between them. And because the terms decide the division, reciprocal demand is what decides how the surplus is shared.²

2. Mill's idea: the terms of trade settle where the two parties' demands for each other's goods exactly match. At any ratio, each country wishes to buy a certain quantity of the other's product and pay with a certain quantity of its own; as terms shift in its favor it wants more, against it less. The terms settle, Mill argued, at the ratio where the amount each wants of the other's goods equals what the other will supply — where the two reciprocal demands balance, the value of exports equaling the value of imports for each. This is RECIPROCAL DEMAND: not supply and cost alone but the mutual pull of each side's desire for what the other makes. Because the terms decide the division, reciprocal demand decides how the surplus is shared.

⁂

From this Mill drew a conclusion that overturns the natural intuition about strength in a bargain. One would think that a country with a powerful, urgent demand for foreign goods — a people who crave what only the other can supply — would be in a strong position. The opposite is true. The country whose demand for the other's goods is the more intense and the less easily reduced finds the terms settling AGAINST it: because it will keep buying even as the rate worsens, the rate worsens, and it ends up surrendering more of its own goods for each unit of what it wants, carrying away the smaller share of the joint surplus. The country whose demand is mild and elastic — which will readily cut back its purchases if the terms turn unfavorable — holds the terms in its favor, for its willingness to walk away forces the other to offer better. Eagerness, in Mill's analysis, is weakness; the ability to do without is strength. The side that wants the trade more pays more for it and keeps less of the gain, while the side that can take it or leave it commands the better terms and the larger share. The surplus flows toward indifference and away from need.³

3. Mill's conclusion overturns the natural intuition about bargaining strength. One would think a country with an urgent demand for foreign goods is in a strong position; the opposite holds. The country whose demand is more intense and less easily reduced finds the terms settling AGAINST it: because it keeps buying as the rate worsens, the rate worsens, and it surrenders more of its own goods per unit, keeping the smaller share. The country whose demand is mild and elastic — ready to cut back if terms turn — holds the terms in its favor, its willingness to walk away forcing better offers. Eagerness is weakness; the ability to do without is strength. The side that wants the trade more pays more and keeps less. The surplus flows toward indifference and away from need.

Mill framed the doctrine for trade between nations, but it is the general law of how any surplus divides between two parties, and it reaches far beyond customs houses. Wherever a buyer and a seller, a landlord and a tenant, an employer and a worker, two firms or two friends, come together over a deal that would benefit them both, the same logic governs the split. The party with the better alternative — the one who loses least by walking away, whose demand for this particular deal is the more elastic — captures the larger share of the surplus; the party with the worse alternative, who needs this deal and has nowhere else to turn, captures the smaller. The single buyer facing many sellers, the worker with many employers bidding for him, the firm with substitutes at hand, all command good terms; the seller of a perishable good at day's end, the worker with one factory in town, the buyer who must have the thing today, all take what they can get. The price settles where the two demands balance, and it settles nearer the reservation of whichever party is the more desperate, handing the surplus to the one who can most easily say no.⁴

4. Mill framed the doctrine for trade between nations, but it is the general law of how any surplus divides. Wherever a buyer and seller, landlord and tenant, employer and worker, two firms or two friends meet over a mutually beneficial deal, the same logic governs the split. The party with the better alternative — who loses least by walking away, whose demand for this deal is more elastic — captures the larger share; the party who needs the deal and has nowhere else to turn captures the smaller. The buyer facing many sellers, the worker many employers, the firm with substitutes at hand command good terms; the seller of a perishable at day's end, the worker with one factory in town, the buyer who must have it today take what they can get. The surplus goes to the one who can most easily say no.

So the surplus, created jointly by the act of exchange, is divided not by any rule of fairness but by the relative strength of the two parties' need — by who can more easily do without. Mill located that strength in reciprocal demand: the terms of trade, and so the division of the gains, settle where each side's desire for what the other holds comes into balance, with the terms turning against whichever side wants the exchange more. This is why the same surplus, the same gains from the same trade, may go nine-tenths to one party and one-tenth to the other, depending on nothing about the value created and everything about the bargaining position of the two who create it. And it points to the next move in the contest. If the division of the surplus depends on bargaining power, then a party who can MANUFACTURE bargaining power — who can make the other side more dependent, more eager, with fewer alternatives — can swing the division its way. The seller who can make his product one of a kind, so that buyers who want it have nowhere else to go, has done exactly this; he has bought himself the better terms. How sellers acquire such power, and what it does to the surplus, is the work of the next plate. The next plate is the brand.⁵

5. The surplus, created jointly, is divided not by fairness but by the relative strength of the two parties' need — by who can more easily do without. Mill located that strength in reciprocal demand: the terms, and so the division, settle where each side's desire for the other's goods balances, turning against whichever wants the exchange more. So the same gains from the same trade may go nine-tenths to one party, depending on nothing about the value created and everything about bargaining position. And it points ahead: if division depends on bargaining power, a party who can MANUFACTURE power — make the other more dependent, with fewer alternatives — can swing the division its way. The seller who makes his product one of a kind has done exactly this. Next: the brand.

John Stuart Mill answered how the jointly created surplus is divided between the two parties to a trade. The classical economists had shown that both gain and had bounded the terms within the band between their two costs, but were silent on where within that band the terms settle. Mill's doctrine of reciprocal demand filled the gap: the terms of trade come to rest where each side's demand for what the other holds exactly balances the other's willingness to supply, so that reciprocal demand, not cost alone, fixes the rate of exchange and thus the division of the gains. From this came his striking result that the terms turn against the party with the stronger, less elastic demand — that eagerness is weakness and the power to do without is strength — a law that governs not only nations but every two-party bargain, handing the larger share to whoever can most easily walk away. The surplus divides by bargaining power, and bargaining power can be manufactured. The next plate is the brand.