Last week’s Brexit vote by the United Kingdom came as a surprise to many. In a single day of broad democratic participation, the majority of U.K. voters chose to undo 40 years of integration at the heart of the world’s largest trading bloc. Free trade agreements (FTA) have had an impressive run.

Over the last 25 years, the value of trade has grown by five times, according to the World Bank. Unfortunately, trade growth has slowed in recent years, with the value of 2015 global trade down 14 percent, according to the CPB World Trade Monitor.

Weak global demand and slowing appetites for trade liberalization are the key factors. While free trade is not dead, the utility of incremental tariff reductions under FTAs is diminishing rapidly.

From a demographic perspective, free trade is evolving to meet political demands for trade “fairness” in the greying developed world as productivity and income growth grind to a halt.

Trade revisionism has dominated recent U.S. politics, to be sure, but the movement is also alive and well in other industrialized countries, particularly in Europe, and has already intensified post the Brexit vote.