Free trade is an American mantra. The Obama administration's commitment to winning "fast-track" status for its cherished Trans-Pacific Partnership trade agreement is part of that tradition. But growing evidence shows that granting full trading privileges to low-income countries on the make is usually costly to the United States.

The U.S. has been in lengthy negotiations with 11 nations around the Pacific Rim, including Australia,Chile, Japan, Singapore and Malaysia. After years of talks, the partners now seem close to an agreement.

That is one reason for the unusual congressional alliance of left-wing Democrats like Sen. Elizabeth Warren, a Massachusetts Democrat, with tea party Republicans like North Carolina Rep. Walter Jones lined up against the trade initiative. Policy-wonk tea party fellow travelers, including Wisconsin Republican Rep. Paul Ryan and Texas Republican Sen. Ted Cruz, support the deal — as do many mainstream economists.