Markets have settled on a number. America’s tariff on most of its trading partners sits at 15%, and the figure has barely twitched in a year. That stability is the trap. The 15% has held while the legal ground beneath it was struck down, replaced, struck down again and rebuilt under a third statute. The rate is the one thing not moving. Everything underneath it is.
This is the part the consensus underprices. A tariff is usually read as a price: a level that feeds margins, inflation and the terms of trade. A tariff imposed by presidential power is also a legal instrument with a shelf life, and the shelf life is where the information sits. There is a larger contest inside it, too. A great power is holding a tariff wall in place by hopping from one emergency power to the next as the courts strike each one down: a quiet test of how much the executive can tax without Congress, refought every few months. The market reads that test, imperfectly, as a number. Watch the rate and you learn little. Watch which statute is carrying it, and when that statute breaks, and you are reading a calendar of discrete events, each one able to move the carry trade, the business of borrowing where money is cheap to invest where it is dear, more than the tariff itself ever will.
The half-life, not the height
Run the past four months as a sequence and the pattern is hard to miss. In February the Supreme Court held, 6-3, that the International Emergency Economic Powers Act does not let a president levy tariffs, and collection of the reciprocal duties stopped within days. Washington rebuilt the wall at close to the same height under Section 122 of the Trade Act, a balance-of-payments provision pressed into service that carries its own guillotine: a hard 150-day limit. That clock runs out on 24 July. A trade court has already ruled the Section 122 surcharge unlawful; an appeals court stayed that ruling, so collection continues while the question hangs. And waiting to catch the rate when Section 122 lapses is Section 301, the forced-labour action announced on 2 June against 60 economies, with hearings on 7 July and no built-in sunset. Section 301 lands lower, at 10% to 12.5%, so the wall does not carry over cleanly: it is rebuilt below the old line, with stacking on Section 232 and most-favoured-nation duties lifting some products back toward it.
Each is a different vessel with a different way of breaking. IEEPA broke on statutory authority. Section 122 breaks on the calendar. Section 301 is slower to stand up and harder to knock down, because it rests on a record and a hearing. The rate they each carry is much the same. The half-life is not. That is the variable worth watching, and most of the commentary is still fixed on the level.
A second clock runs alongside: refunds. The Supreme Court left the mechanics of repaying the invalidated duties to the lower courts, and almost 2,000 importers are already in the queue. If the sums are large enough, a refund cascade is a fiscal event and a confidence event at once, with no equivalent in a world where tariffs simply sit at a level.
Why the number misleads
Trade lawyers read the Section 301 move as a deliberate step to avoid a gap when Section 122 expires. The effect, whatever the intent, is a wall held at roughly the same height while the bricks underneath are replaced a course at a time: hold the height and swap the legal basis, and revenue and protection survive each defeat in court.
The reflexive part is narrower than it looks. The flat rate is not what crowds the carry; the gap between American and Japanese yields does that. What a motionless tariff does is quieter: it removes one source of volatility from the screen, and a suppressed tail flatters a crowded trade, making it look safer than the legal ground beneath it. The events that matter are not rate changes but ruptures: a court date that goes the wrong way, a sunset that arrives with no replacement ready, a refund order that turns a line item into a cash call. None shows up in the headline number until after it has moved the things that price off it.
The only clean path down
Which brings it to positioning, and to the part that travels well past Japan. The asymmetry sits in the carry trade, not in any broad direction for the dollar. A rate that grinds sideways at 15% keeps the funding machine intact: cheap borrowing in low-yield currencies and the crowded shorts against them left undisturbed. Nothing in a stable rate forces anyone to do anything. The forced flow, the kind that detonates rather than drifts, appears only if a vessel ruptures and the market reads it as Washington losing its grip on its own tariff regime.
That is the one clean route to a sharp move, and it runs one way. August 2024 is the template: a crowded funding currency snapped higher in days, not on a change in any rate but on a jolt to the trade the whole market was leaning on. The leaning is real and current. Speculative funds were heavily short the yen in late June, a net bet of around 115,000 contracts, the kind of one-way book that turns an orderly move into a stampede. A legal rupture in the tariff regime is that kind of jolt. It would hit the yen hardest, because the yen is still the funder of first resort, though the Bank of Japan’s rate rises have made it less of a one-way bet than in 2024 and no longer the only one: the Swiss franc plays the same role. Any currency held short against a low yield is open to the same reflex. The tariff rate will not flash the warning. The legal calendar might.
So the signal is not in the level. It is in the half-life. The market is priced for a number held deliberately flat, and the carry stacked on top of it is leaning hard one way. What that crowded book is exposed to is the day a vessel breaks with nothing ready to catch the rate: the comment deadline on 6 July, the hearing on 7 July, the Section 122 sunset on 24 July and whatever the appeals courts decide about the refunds behind them. None of it will move the 15% by much. All of it could move everything that trades against it.
The wall is unlikely to come down. The base case is that the rate holds, the vessels keep getting rebuilt and the carry trade is left to do what it does. But the deeper question is not about trade at all. It is whether a government can keep taxing by emergency decree faster than its courts can stop it, and the answer is being written one struck-down statute at a time. The carry book is simply the most sensitive instrument now reading it. The number on every screen says calm; the law underneath it does not.