Newly released polling data from Gallup shows that half of all Republicans see foreign trade as mainly a threat to the United States.

This level of skepticism toward international trade has remained high among the GOP base since Gallup started collecting polling data on the topic.  By comparison, Democrats and independents both have much lower levels of concern about foreign trade, with each group at 37% of its membership viewing foreign trade as mainly a national threat.

Concerns over the negative economic impacts of foreign trade by Republicans are well-founded.  Since 1960, there has been a strong negative relationship between the proportion of the U.S. economy engaged in trade and the corresponding rate of growth for real per capita GDP.

In short, over the past 55 years, more trade correlates with lower economic growth.  During the 1960s, the U.S. averaged a trade volume at 9.4% of GDP and an average annual rate of real per capita GDP growth at more than 3.3%.  Since 2000, the volume of trade has averaged 26.5% of GDP (reaching over 30% since 2011), while real per capita GDP growth has averaged just 1.0% per year – less than one third the economic growth rate of a half-century ago.

The problem has become a key issue in the GOP primaries.  Donald Trump has called for "fair trade" rather than "free trade," making it one of his core campaign planks.

The lack of fairness Trump is speaking of is exemplified by the unbalanced nature of American trade with the world since it began running continuous annual balance of trade deficits in the 1970s.  These never-ending and perpetually increasing deficits have played a fundamental role in the ever slowing rate of economic growth over this time frame.

The trade in goods deficit reached $759 billion in 2015, and the modest trade in services surplus of $227 billion was nowhere near enough to offset the imbalance, resulting in an overall total goods and services trade deficit at $532 billion for the year.  During the higher growth period of the 1960s, the U.S. ran a small total trade surplus.

In order to get back on track economically, America needs "fair and balanced" trade, just like the Fox News slogan.