The short answer is that they aren’t better than the free market. However, that presupposes the global trade market is inherently “free” to begin with. Theoretically, trade between two countries with floating currencies (meaning unaltered by policy) is self-correcting.  The deficit country’s currency weakens, making its exports cheaper and closing the gap. When an imbalance persists over decades, the view is that the surplus country is interfering through policy. That policy may subsidize industries or manage the exchange rate to maintain the export advantage. Tariffs are meant to counteract those overseas policies. As to why it’s an exercise in futility: a tariff is a tax on domestic consumption at home; it invites retaliation anyway, and it does nothing to change the math that a wealthy country consuming more than it produces has to get the difference from somewhere. Tariffs erode the benefit of importing cheaper goods and services. Yes, we are exporting dollars to pay for them, but if we assume consumption remains constant, do we want to pay more or less?  Keep in mind, too, that exporting dollars abroad in that process is one of the reasons the dollar remains the world’s reserve currency. Tariffs can be useful strategically for goods and services with a national security interest, rather than applied broadly and equally.