Most of the presidential candidates agree that past trade treaties have had negative effects on US workers and that future trade treaties need to take a different approach. This would appear to be bad news for the Trans-Pacific Partnership (TPP) and other trade agreements that are in various stages of negotiation and ratification. Bernie Sanders has been a long-standing opponent of the TPP, Hillary Clinton has recently converted to opposing it, Donald Trump appears to oppose it but with bluster and little substance, Ted Cruz has not been clear on where he stands, and John Kasich supports the TPP.
Support for the arguments against recent trade treaties has recently come from an unlikely source, Clyde Prestowitz, who served in a senior position in President Reagan’s Department of Commerce and as President Clinton’s vice chairman of the Commission on Trade and Investment in the Asia-Pacific Region. 
Prestowitz writes that after the 2001 agreement that let China join the World Trade Organization, our trade deficit with China soared from $80 billion to $370 billion. The best estimates are that imports from China have cost the US about 2.5 million jobs. This occurred despite assurances to Congress and the public that this agreement would dramatically reduce the trade deficit with China and create US jobs. These assurances were given by very senior members of the Bush administration including the Secretary of Commerce and the US Trade Representative.
The results of the US-Korea Free Trade agreement of 2012 are similar. Our trade deficit with Korea increased from $13 billion to $28 billion, costing the US roughly 90,000 jobs. However, the same promises of a reduced trade deficit and US job growth were made in promoting this trade deal.
Prestowitz concludes that “None of the trade agreements have eliminated [the trade deficit], or even reduced it, as promised, and none of them have come close to achieving other promised benefits.”
So, he poses the question of why both political parties and numerous well-educated officials have persisted in making and supporting these trade agreements, as well as using the same old arguments to sell them to Congress and the public. He gives two answers. The first is that the real reason for these trade agreements is to strengthen the US’s geopolitical position, not to improve the economic welfare of its workers. As an example of this, Prestowitz, to this day, defends the North American Free Trade Agreement (NAFTA) with Mexico and Canada as an appropriate step to counter the growing geopolitical influence of China and other Asian countries.
His second answer is that many experts base their analyses on a theoretical and outdated model of trade and globalization. This model assumes full employment, fixed exchange rates, no flow of investments across borders, no transfers of technology, and no costs due to displaced workers losing one job and having to find another one. In reality, the US has rarely, if ever (depending on the standard you use), been at full employment. Exchange rates have been floating and not fixed since the 1970s and some countries, notably China, systematically manipulate the exchange rates for their currencies. The flow of investments, of financial deals and money, across borders is greater today than the flow of goods (traditional trade). China and Japan, among others, have made the transfer of technology to their countries a condition of allowing access to their workforces and markets. And we know how painful the displacement of workers has been. New jobs have been hard to find and, for those lucky enough to get a new job, the pay and working conditions are typically far worse than they were with their previous job.
Another answer, that Prestowitz doesn’t present, is that large, multi-national corporations have great power in Congress and our federal government. They are the main beneficiaries of these trade treaties. Through campaign contributions (largely by their senior executives), lobbying, and the revolving door between them and positions in the federal government (including the executive branch and Congress), they have tremendous influence on trade and other policies.
It is encouraging to see that when the public is paying attention, as it does during a presidential campaign, and when there is at least one candidate who presents a strong position and argument against the TPP and other trade treaties, that other candidates will forego their allegiance to corporate power (and money) and take a position in opposition to the TPP. It will be our job, as voters and constituents, to make sure that the next president follows through on his or her campaign commitment to oppose the TPP and to work to ensure that trade treaties benefit US workers and the US economy.
 Prestowitz, C., 3/22/16, “Trading down and up,” The Boston Globe