Welcome to the documentary here on the BBC World Service. I'm Edward Sturtin and I'm on the

trail of protectionism in the United States.

I'm driving down Cameron Street in a place called Steleton in Pennsylvania and if you want to know why

trade looms so large in this presidential campaign you only have to look over on

my right they'd be making steel here since the 1860s something's coming off the production line today but mostly

over here I can see nothing but mile upon mile of empty warehouses piles of rusting pipes

and silent plant of course many of the problems here date back a long time, but competition and particular

competition from China is being blamed for many of America's problems in manufacturing today and the steel industry say that they've had

the layoff 12,000 workers in the last year because of competition from China.

I have been banging this I loathe Mr. Trump but unfortunately this issue which is very salient has been left on the table

for a demagogue like him to take advantage of.

The anguish there of one of those mainstream Republicans who

resent the way their party has, as they see it, been hijacked. One of the most

striking features of this most unusual American presidential campaign

is the way protectionism has become

such a powerful rallying cry.

And not just on the Republican side,

have a listen to these two speeches.

I pledge to never sign any trade agreement that hurts our workers or that diminishes our freedom and our independence.

We will never, sign bad trade deals. America first again.

America first.

Since 2001 we've lost 60,000 factories in America, a lot of that having to do with

...