An employee works on the assembly line installing parts on the Duratech 35 V6 engine at the Ford Motor Co. Engine Plant in Lima, Ohio.

Mexico didn't foist NAFTA on the United States, despite President Donald Trump's constant claims that the U.S. loses "so much money" on the deal. We did it to ourselves, and we did it deliberately.

Corporations wanted to create in Mexico a low-wage haven where they could shift production, expecting us to happily buy the imported goods built with cheap Mexican labor—while exporting our jobs.

Trump's new trade pact, the United States-Mexico-Canada Agreement, includes sweetheart deals for the oil, gas and pharmaceutical industries that create huge problems for consumers. But it also perpetuates the original NAFTA's core problem, the one the president himself has talked about most: shifting U.S. production to Mexico.

If Mr. Trump is unwilling to tackle the central flaw of what he has called "the worst trade deal in history," his won't be any better.

Before NAFTA, we did not have a significant trade deficit with Mexico. In the NAFTA world, we have run a stubborn $100 billion deficit year in, year out. According to the Economic Policy Institute, by 2013 NAFTA had displaced 852,000 U.S. jobs, mostly in the manufacturing sector.

How bad is it right now? Let's focus on autos, the biggest sector overall and the one most important to Michiganders. U.S. auto imports from Mexico continue to break records, doubling between 2011 and 2018. They jumped again in the first quarter of this year. In total, four-fifths of cars that Mexico exports are exported to the U.S.

When manufacturers—like General Motors in Warren, Michigan—close up shop to move plants to Mexico, there are fewer jobs for American workers. And where opportunities do exist, wages must compete with the $1-$2 per hour wages in Mexico. GM now makes nearly a quarter of the cars it sells in the U.S. in Mexico, and that number is only poised to grow.

We can protect American workers by stopping the flow of U.S. jobs south of the border. But to do that, any new trade regime must raise the standard of living for Mexican workers. The deeply entrenched Mexican system of fake unions and so-called protection contracts must be replaced by real worker power through authentic unions and actual collective bargaining.