Donald Trump says American manufacturing is declining. It isn't.

One of Donald Trump’s big themes at Monday’s night’s debate has been to blame trade — and especially Bill Clinton’s trade policies — for the decline of America’s manufacturing sector.

“Your husband signed NAFTA, which was one of the worst things that ever happened to the manufacturing industry,” Trump said to Clinton. “You go to New England, Ohio, Pennsylvania, you go anywhere you want, Secretary Clinton, and you will see devastation where manufacturing is down 30, 40, sometimes 50 percent.”

Of course there are some towns in Ohio, Pennsylvania, and elsewhere in America where factories have closed and hence manufacturing has gone down. But for the country as a whole, manufacturing output is actually up about 50 percent since the NAFTA agreement took effect in 1994.

It’s true that over the same period, manufacturing employment declined by about 14 percent, from 22.7 million workers to 19.6 million.

But that’s not a sign that America’s manufacturing sector is in decline — it’s a sign that American manufacturers are becoming more and more productive. And ultimately, this growing productivity is what raises American living standards.