President Trump officially withdrew the U.S. president’s signature from the Trans-Pacific Partnership today. Could the U.S. still renegotiate TPP? Or is the door to this agreement closed?

It signals that the President no longer wishes the United States to become bound by TPP and that he does does not intend to submit the agreement to Congress.  Nothing prevents President Trump from deciding at some future point, however, that he wishes to renegotiate TPP, sign it, and submit the renegotiated agreement to Congress.  Whether our TPP partners would consider us credible negotiators and want to deal with us under these circumstances, of course, is a separate question.  The timeline would also be relevant, as existing trade promotion authority (the so-called “fast track”), which promises an up or down vote on a trade agreement by the Congress within a limited time and precludes Congressional amendments, expires July 1, 2018.  Without trade promotion authority, our trading partners know that the chance of Congressional approval of an agreement without Congressional demands for renegotiation diminish, and the United States will have even more difficulty persuading our trading partners that it is worthwhile to engage in negotiation.

Why are trade agreements good, and bad, for the U.S.? And has the U.S. been fairly consistent in advocating free trade with its neighbors and allies with negotiated agreements—perhaps since the 1934 Reciprocal Trade Agreements Act (RTAA)?

Paul Samuelson, the first American Nobel Laureate in economics, once suggested that the virtues of free trade are one of the very few things on which most every economist can agree.  Liberal trading rules allow nations to specialize in the production of tradable goods and services at which they are comparatively best, in turn allowing greater global output of goods and services for the same overall inputs.  In short, the pie gets bigger, and every nation in principle can enjoy a larger slice.

Modern trade agreements also do much more than simply lower barriers to trade at the border such as tariffs and quotas.  For example, they seek to open trade in service sectors where border measures are generally less important, to eliminate costs due to unnecessary regulatory heterogeneity, and to enhance protection for intellectual property rights (the latter is of uncertain value from a global perspective, but undeniable benefit to major producers of intellectual property such as the United States).