Post hoc, ergo propter hoc means “after this, therefore, because of this,” and is a logical fallacy. Every action has consequences, but subsequent events may or may not be related to the prior event. The concept gets expressed slightly differently, and in English, as “correlation does not imply causation.”

I have been following the Trans-Pacific Partnership aka TPP trade deal just a little bit. I’ve also been following the developing battle between President Obama and Senator Elizabeth Warren (D-Mass.). He supports the TPP; she doesn’t.

Senator Warren is one of my heroes. She’s scary smart, focused on regular people, and seemingly incorruptible. She may be wrong about the TPP, too.

When trade matters come before Congress, all roads lead back to NAFTA, the North American Free Trade Agreement. People on my side of the divide argue with ease that NAFTA killed American industry. Take, for example, Report: NAFTA Has Cost 683,000 Jobs—and Counting. Relying on an Economic Policy Institute study, James Parks claims America lost 682,900 jobs between 1994 and 2011 because of NAFTA. And the basis for this claim?

The main reason for the job loss is a $97.2 billion trade deficit with Mexico. In 1993, one year before NAFTA was implemented, the United States had a $1.6 billion trade surplus with Mexico that supported nearly 30,000 U.S. jobs.

I’m not bothering with how a trade swing with Mexico of $98.8 billion over 18 years equals 682,900 jobs. I don’t care, and here’s why:

1. No one knows, or can ever know, what the trade deficit with Mexico would have been in 2011 without NAFTA. Lower maybe, but how much lower. Or maybe higher, because of other factors. Counterfactuals can never be proven, plain and simple.
2. According to the Bureau of Labor Statistics, non-farm employment in 2011 totaled slightly more than 131,000,000 people. That means the claimed loss of employment is barely more than 0.5%, or one of every 200 employees.

Maybe I sound like I don’t care about Dennis Smith and his family, after he lost his manufacturing job in North Carolina in 1995. (Denny doesn’t exist, but someone like him surely does.) I do care, but my focus is on the absence of an intelligent discussion. Yes, Denny may not be working, but are we having an intelligent discussion if the only talking point is a dubious claim that Denny is home because of NAFTA?

There’s another issue about trade agreements which must be mentioned. Agreements with other nations are always all about the possible! Those of us who occupy the left like to be smug about the Right when it talks about American Exceptionalism. Senator John “Uncle Fester” McCain’s almost daily demand for a new war also sets us off. But we can’t get to where we want via intransigence, just like our friends on the Right can’t get what they want by invoking Exceptionalism or starting new wars. It’s a global village!

Truth be told, I don’t know whether the TPP is or is not a good deal. Our Ambassador to Japan, Caroline Kennedy, says it’s what we need here. I put lots of faith in Ambassador Kennedy—this one, not her grandfather Joe—because she’s very smart, she does not need the job, and because no one’s going to get her to do anything she doesn’t want to do.

Here’s some reality. Congress gets a limited opportunity to really understand trade deals. That’s bad, but it’s not a new phenomenon. And the rest of us? We can’t begin to know or understand TPP or any other trade deal.

For me the choice is easy. Free trade carries with it positive values. The case against it is replete with post hoc, ergo propter hoc illogic about lost jobs and environmental problems. Further, a trade deal can’t be measured against what we want, as we must assume our representatives sought the best deal for our country. Instead, it must be measured against no deal, for that’s the real alternative.

P.S. Before my Leftie friends start hollering about the Chamber of Commerce, etc., I know the TPP favors corporations. (You think, maybe, that we’re going to resurrect the whole “power to the people,” unions, and “don’t buy grapes” thing on the back of the TPP?) I also know, though, that we elected Barack Obama, not Mitt Romney, and I don’t think I need to say anything else.