In an interview with the New York Times editorial board, Donald Trump said that he would impose a 45% tariff on all goods from China. That is, to put it mildly, a really bad idea, and a number of commentators have already taken it to task.

I’d like to focus on what Donald Trump said immediately after he proposed a 45% tax on Americans who buy things that were made in China. According to the New York Times:

Mr. Trump added that he’s “a free trader,” but that “it’s got to be reasonably fair.”

Unfortunately, Trump is far from the first politician to adopt the “free but fair trade” line. Many of the other candidates vying for the Republican nomination for President in 2016 have employed the trope in some form this election cycle. (See, for example, Mike Huckabee, Rick Santorum, Bobby Jindal, Carly Fiorina, Jeb Bush, Marco Rubio.) Some of these candidates, like Trump, are economic nationalists who openly advocate mercantilist economic policy.

Many of the others are merely politicians. They probably believe in the value of free trade, but when departing from that principle is politically expedient, they need some way to defend themselves. Vague appeals to “fairness” are uniquely well-suited to that task.

The alternative to free trade is not “fair trade.” The choice is between free trade and protectionism. If you think a small amount of protectionism is good, then you do not support free trade. This is important because the economic case for free trade is a case for free trade, not partially free trade or mostly free trade.

Tariffs, quotas, and subsidies are bad economic policy in each instance. Some trade barriers are more harmful than others, but there is not a correct quantum of protectionism you can support while still being a “free trader.”

Perhaps it’s a good thing that even when espousing protectionism, political candidates feel the need to proclaim their support for economic liberty. Still, it would be better if their hypocrisy were called to task more often.