A tariff is announced as a charge on another country's goods, and the mechanics of collection make that description misleading almost immediately. The money is paid domestically and the effects scatter.
The importer writes the cheque
Customs collects duty from the party bringing goods across the border, which is a domestic company, and the payment is made before the goods reach any customer.
Whether the foreign producer ultimately bears any of it depends on bargaining power. A supplier with few alternative buyers may cut its price; one with many will not.
In practice the split varies by product, and much of the cost travels forward into wholesale prices rather than backward into the exporter's margin.
Inputs are taxed alongside finished goods
Modern manufacturing imports components, and a tariff aimed at protecting a domestic industry frequently raises the cost of parts that the same industry buys.
A firm assembling products domestically can end up paying more for its inputs than a competitor importing the finished item, which inverts the intended protection.
Exclusion processes exist to handle this, and they create their own administrative contest as firms argue over which components qualify.
Trade reroutes rather than stopping
When a tariff targets goods from a particular origin, shipments can be routed through a third country where minor processing changes the declared origin.
Rules of origin determine how much transformation is required, and enforcing them means inspecting production processes abroad, which is slow and difficult.
The observable result is often a fall in direct imports from the targeted country and a matching rise from its neighbours, with the goods themselves largely unchanged.
Retaliation is chosen for political effect
Countries responding to tariffs select their targets to concentrate pain in politically sensitive regions and industries rather than to maximise economic symmetry.
Agricultural goods are common choices because production is geographically concentrated and the affected producers are organised and visible.
That turns a dispute about one sector into a negotiation involving several unrelated ones, which is the intended effect.
The adjustment takes longer than the politics
Building domestic capacity to replace imported goods requires capital investment, permits, skilled labour and years of lead time.
Firms will only commit if they believe the tariff will outlast the government that imposed it, and that belief is hard to establish when trade policy shifts between administrations.
So the short-run effect is higher prices, and the long-run effect depends on a durability that tariffs are rarely able to promise.