美國總統特朗普已經決定對進口鋼材和鋁材加征關稅了，這也標志著特朗普鐵了心要開貿易保護主義的倒車。據《紐約時報》報道，這似乎也是特朗普首席經濟顧問加里·寇恩本周宣布辭職的原因。

特朗普稱，加征關稅的目的是為了促進國內就業。批評人士則指出，因關稅而毀掉的工作，將會比關稅帶來的工作還多。

兩方的看法其實都不全面。關稅不會改變美國就業市場的工作總量，它只會改變改變就業市場的結構，同時使我們變得更窮，經濟效率更低下。

經典學派的自由貿易論者認為，當人們可以自由進行跨國貿易時，各國生產者會根據自身專長，生產對其來說最高效的產品。美國的鋼鐵產量在過去十年間下降了近20%，而進口鋼材和鋁材的數量相應增加，這表明美國資本和工人在其他行業獲得了更好的就業和運用。

從總數看，貿易并不會帶來工作，也不會毀掉工作，因為從鋼鐵或鋁材行業的就業流失數，必然會被美國出口行業以及使用鋼材、鋁材生產產品的其他行業的就業增加數所抵消。同理，關稅為鋼鐵和鋁材行業創造的就業增加數，也必然導致出口行業以及使用鋼材、鋁材生產產品的行業（如汽車、建筑、啤酒、軟飲等）的就業流失數所抵消。

總長期就業數很大程度上取決于勞動力市場的大小以及對勞動力市場的調節，所以所謂特朗普的關稅政策會刺激或抑制就業的說法統統都是偽命題。關稅政策真正會引起改變的，是美國勞動力市場的就業結構，和美國工業的產品結構。而此次的政策調整只會讓這二者向不利于美國的方向發展。

President Donald Trump has, unfortunately, decided to deliver on his protectionist campaign promises by imposing tariffs on steel and aluminum. According to the New York Times, the tariff decision appears to have been the impetus behind the resignationof Trump’s top economic advisor, Gary Cohn, on Tuesday.

The president claims tariffs create jobs. His critics say tariffs will destroy more jobs than they create.

Both sides misconstrue the situation. These tariffs won’t change the total number of American jobs; they will change the mix of jobs in a way that will make us poorer and less productive.

The classic case for free trade argues that when people are free to trade across national borders, the producers in each country will specialize in the products they make most efficiently. The fact that U.S. steel production has fallen nearly 20% in the last decade, while steel and aluminum imports have increased, indicates that U.S. capital and laborers are better employed in other industries.

Trade neither creates nor destroys jobs on net, because the loss of jobs in a steel or aluminum industry that competes with imports is offset by job creation in U.S. export industries and other industries that use steel and aluminum in whatever they produce. Similarly, tariffs on steel and aluminum create jobs in those industries at the expense of jobs in export sectors and those that use steel and aluminum, such as the car, construction, beer, and soft drink industries.

Total long-run employment is largely a function of the size the labor force and labor market regulations. So claims that Trump’s policies will either create or destroy jobs on net are bogus. Again, it’s the mix of jobs and what we produce in America that tariffs change—and in this case, that will be for the worse.

今年一月，特朗普批準了對進口洗衣機征稅，但其影響遠遠不如此次對鋼鐵和鋁材加征關稅的影響。在美國對進口洗衣機征稅后，LG等洗衣機廠商立即提高了售價。可以想見，受此政策影響，不少美國廠商肯定會大量生產洗衣機，享受貿易保護政策的紅利。然而這些資本和勞動力本來是可以用于生產其他更有價值的產品的。

雖然可能會帶來一些不利影響，但洗衣機關稅的負作用也是有限的，畢竟洗衣機是消費品，不是生產資料。而對作為生產資料的鋼鐵、鋁材加征關稅，會在整個經濟中引起連帶效應，在一個個行業造成勞動力和資本的錯誤配置。

首先，美國國內生產的汽車和易拉罐肯定會變少，同時企業家也會改變產品的生產方式，比如更多的可口可樂將用塑料瓶而不是易拉罐包裝。這樣一來，資本和勞動力就會向塑料行業轉移，其他行業部門必然因此蒙受損失。加征鋼鐵和鋁材關稅所引起的此類調整或將數以億次計，后果是難以估量的。

價格在任何市場經濟中都起著關鍵的調節作用，它說明了資源的相對稀缺性，告訴企業家們如何組織生產才能創造最大的經濟蛋糕。而鋼鋁關稅則會扭曲價格結構，虛假抬高鋼材和鋁材的相對稀缺性。這樣一來，任何需要用到這些材料或其替代物的生產過程都會變得更加昂貴，同時也更低效。

所以說，特朗普的關稅政策不會導致美國經濟的就業率下降，但它會使我們變得更窮和更低效。這是百害無一利的政策。（財富中文網）

本文作者Benjamin Powell是美國獨立研究所研究員、自由市場研究所主任兼德州理工大學經濟學教授。

譯者：樸成奎

The steel and aluminum tariffs will be much more harmful than the tariffs Trump imposed on washing machines in January. Indeed, immediately after those tariffs were imposed, washing machine companies such as LG increased their prices. The tariffs will also result in the production of a few too many American-made washing machines, when we can better use that labor and capital to produce more valuable products.

But even taking these consequences into account, the tariffs’ negative impact will be limited: Washing machines are consumer goods, not inputs for other products. On the other hand, steel and aluminum are used in other production processes. Tariffs on those goods will ripple through our economy, misallocating labor and capital in one industry after another.

The U.S. will produce fewer cars and beer cans, but entrepreneurs will also change how products are made. More Coca-Cola will come in plastic bottles than in aluminum cans. That will shift labor and capital into the plastics industry at the expense of other sectors. These tariffs will cause literally hundreds of millions of such adjustments.

Prices play the key coordinating role in any market economy, signaling the relative scarcity of resources and telling entrepreneurs how to organize production in a way that creates the largest economic pie possible. Steel and aluminum tariffs will distort the price structure by raising prices and indicating that steel and aluminum are more scarce than they in fact are. As a result, any production process that uses those materials, or their substitutes, will become more expensive and less efficient.

No, Trump’s tariffs won’t cost the American economy jobs, but they will make us poorer and less efficient. There is nothing great about that.

Benjamin Powell is a senior fellow at the Independent Institute, the director of the Free Market Institute, and a professor of economics at Texas Tech University.