This is interesting (not sure how accurate or complete it is, mind):
Pros
The TPP boosts exports and economic growth, creating more jobs and prosperity for the 12 countries involved. It increases exports by $305 billion per year by 2025. U.S. exports would increase by $123.5 billion, focusing on machinery, primarily electrical, autos, plastics, and agriculture industries.
It does this by removing 18,000 tariffs placed on U.S. exports to the other countries. The United States has already withdrawn 80 percent of these tariffs on imports. The TPP evens the playing field.The agreement adds $223 billion a year to incomes of workers in all the countries, with $77 billion of that going to U.S. workers. (Source: “TPP Fact Sheet,” US Trade Representative.)
All countries agreed to cut down on wildlife trafficking, especially elephants, rhinoceroses, and marine species. It prevents environmental abuses, such as unsustainable logging and fishing. Those that don’t will face trade penalties.
Cons
Most of the gains in income would go to workers making more than $88,000 a year. Free trade agreements contribute to income inequality in high-wage countries by promoting cheaper goods from low-wage countries.
That would be particularly true for the TPP because it protects patents and copyrights. Therefore, the higher-paid owners of the intellectual property would receive more of the income gains.The agreement regarding patents will reduce the availability of cheap generics, making many drugs more expensive.
Competitive business pressures will reduce the incentives in Asia to protect the environment. Last but not least, the trade agreement could supersede financial regulations. (Source: “Eyes on Trade,” Public Citizen, September 12, 2013.)
Emph mine - suggesting that the TPP would have helped exporters while those competing with importers are already suffering.
(also doesn’t really highlight the bit about letting companies sue countries).
I am not against free trade, I think isolation and trade wars are a bad idea (which Trump will shortly demonstrate to the class). I think a trade agreement as a bloc to help remove tariffs but protect low-paid workers would be a good idea, but I always got the impression that the TPP was a massive overreach/corporate handout, and trying to hide all the details was a dead giveaway.
I think abandoning the whole idea probably just lets China in to dominate when the TPP was partially intended to shut them out - perhaps why Trump doesn’t like it. But I thought I read somewhere that most of the countries in the TPP already have free-trade agreements with the US, so they won’t all go away.