Susan Atkinson is a writer on energy and climate issues with Citizens Climate Lobby, advocating for bipartisan climate solutions to reduce carbon emissions. She lives in Colorado.

When wildfire smoke drifted south from Canada this summer, President Trump complained that Americans were being “invaded by filthy, polluted and unhealthy air” and threatened tariffs on Canadian goods. Canadian leaders responded that when smoke flowed north from U.S. fires in previous years, they sent firefighters — not threats.

It’s an easy political exchange. But it misses the larger point. Smoke doesn’t stop at customs checkpoints. Neither does carbon pollution.

If we’re serious about protecting American health, forests, farms and businesses, the question isn’t how to punish Canada for one season’s smoke. The question is how to reduce the carbon pollution that is making extreme wildfire conditions more common across North America.

One of the oldest ideas in economics is the “tragedy of the commons.” When everyone shares a resource but no one owns it, everyone has an incentive to use as much of it as possible before someone else does. Think of six kids with six straws sharing one milkshake.

The atmosphere works much the same way.

For generations, we’ve treated the atmosphere as a free dumping ground. Companies pay for labor, equipment, fuel and raw materials, but most of the costs of carbon pollution are paid by everyone except the polluter — through higher insurance premiums, wildfire damage, drought, public health costs and other economic losses.

Markets work best when prices tell the truth.

If a factory dumps waste into a neighbor’s pond, we don’t shrug and call it the cost of doing business. We expect the polluter to pay for the damage. That’s accountability. Air pollution shouldn’t be any different.

A carbon fee applies the same principle. Companies that produce fossil fuels pay a steadily rising fee based on the carbon those fuels will release. Businesses and consumers then have every incentive to find cleaner, more efficient alternatives — not because Washington tells them what to buy, but because the market rewards lower-emission choices.

The money doesn’t stay in Washington. Under a carbon fee and dividend system, the revenue is returned directly to American households. Families receive dividend payments that help offset higher energy costs. Those who reduce their carbon-based energy use come out ahead financially.

There is one more piece.

If America adopts a carbon price while imports from countries without similar policies remain cheaper, manufacturers could simply move production overseas. Global emissions would stay the same — or even increase — while American jobs disappear.

A Carbon Border Adjustment Mechanism, or carbon border adjustment, prevents that. Imports would pay a comparable carbon fee based on the pollution created to make them, allowing American manufacturers to compete on innovation, efficiency and quality — not on who can pollute for free. That’s not protectionism. It’s fair competition.

President Trump’s frustration over smoke recognizes a real problem. Air pollution ignores national borders. But tariffs aimed at one country over one wildfire season don’t address the deeper cause. Wildfires will continue to grow more destructive as long as most of the costs of carbon pollution are paid by everyone except the polluters.

Conservatives have long argued that markets work best when people bear the costs of their own decisions. A carbon fee and dividend applies that same principle to pollution.

A carbon fee and border adjustment don’t replace the free market — they make it work better. Markets only work when prices reflect real costs. Right now, pollution is one of the biggest costs left out of the price.

It follows a simple rule: polluters — not taxpayers — should pay.

Instead of telling businesses exactly how to cut emissions, it lets the market discover the cheapest solutions. Instead of growing bureaucracy, it returns the revenue to citizens while encouraging cleaner production everywhere.

The atmosphere may be shared by all of us. But shared resources don’t have to be free resources.

If smoke crossing the border has reminded us of anything, it’s that pollution doesn’t need a passport. Our policies shouldn’t stop at the border either.