Smoke across the border

CNBC reports that active wildfires in Canada have pushed unhealthy air into broad stretches of the United States, and that President Trump has responded by threatening to fold the cost of that pollution into tariff rates already levied against Canadian goods. I understand the frustration. When harm crosses a border, the injured party reasonably asks who must answer for it. That question is legitimate. The method proposed, however, deserves careful examination before it hardens into policy.

On the nature of the obligation. A tariff is an instrument of commerce — a toll placed on goods in trade. It is calibrated, at its best, to the terms of whatever agreement governs that trade. To repurpose a tariff as a penalty for an environmental tort is to use a commercial instrument for a purpose outside its construction. When we drafted treaties, we labored to name each remedy precisely, because an imprecise remedy creates a new grievance faster than it resolves the original one. I would ask: does the existing trade framework between the United States and Canada — whatever successor agreements have been reached since my era — authorize this surcharge? If it does not, the United States may find itself in breach of its own obligations in the act of demanding satisfaction for another's.

On natural disaster and national responsibility. It is worth noting — and CNBC's report does not settle this point, so I mark it as inference — that wildfires are not always the product of negligent policy. They may be the consequence of conditions no government fully controls. The law of nations has long distinguished between harm a state inflicts by deliberate act and harm that originates in nature and passes through a state's territory. To hold Canada financially liable for smoke as though it were a factory's discharge requires a finding that Canada failed some duty of prevention or mitigation. That finding should precede the penalty, not follow from it.

On the diplomatic instrument. My experience at the treaty table taught me that the moment a nation reaches for a unilateral economic club, the other party reaches for one in turn. Canada is a neighbor of enormous consequence to American commerce, security, and — as smoke itself reminds us — environment. A surcharge announced in the heat of a week's news cycle is not a settlement; it is an opening provocation. The wiser course is a formal diplomatic exchange: a request for information on Canadian fire-management practices, an inquiry into what joint protocols exist for transboundary air quality, and, if negligence is found, a demand framed in the language of the relevant treaty rather than of a press release.

On what should be done. I do not suggest the United States absorb the cost of foreign-sourced harm without recourse. I suggest the recourse be proportionate, grounded in the written terms of the parties' agreements, and pursued through channels designed for exactly this kind of dispute. Anger is not analysis. A tariff surcharge announced in response to wildfire smoke may feel like resolve; it reads, in international law, like improvisation. Let the parties identify the applicable convention, convene under it, and reach a remedy that both can defend to their own people as just — rather than one that each must explain as retaliation.