The Trans-Pacific Partnership trade agreement is being portrayed as a boon for all 12 of the countries involved. But opposition to the agreement may be the only issue that the remaining U.S. presidential candidates can agree on, and Canada's trade minister has expressed serious reservations about it. Are the TPP's critics being unreasonable?

In a word, no. To be sure, the TPP might help the U.S. to advance its goal of containing China's influence in the Asia-Pacific region, exemplified in U.S. President Barack Obama's declaration that, "With TPP, China does not set the rules in that region; we do." But the economic case is not nearly as strong. In fact, though the TPP will bring some gains, they will mainly accrue to large corporations, and come at the expense of ordinary citizens.

In terms of gains, one U.S. government study on the topic projected that, by 2025, the TPP would augment its member countries' GDP growth by a meager 0.1 percent at most. More recently, the U.S. International Trade Commission (ITC) estimated that, by 2032, the TPP would increase America's economic growth by 0.15 percent ($42.7 billion) and boost incomes by 0.23 percent ($57.3 billion).