Shinzo Abe, Japan's prime minister. (Tomohiro Ohsumi/Bloomberg)

THE TRANS-PACIFIC Partnership is a proposed free-trade agreement that will knit the United States and 11 nations of South America, North America and Asia more closely together, while providing a geopolitical counterweight to a rising China. The pact would be especially valuable because Japan is willing to join, which would require a long-overdue opening and restructuring of its protected but lackluster economy. Indeed, without Japan, the world’s third-largest economy, the TPP loses much of its strategic significance.

So it was disappointing to learn that a Sept. 24 meeting between American and Japanese trade negotiators in Washington broke up after only an hour over the same old issue, Japanese resistance to U.S. farm exports, that has plagued the two nations’ dealings for decades. The Japanese departed without touching a sandwich buffet that had been laid out in anticipation of an extended working session, according to the Wall Street Journal.

This is only the latest troubling development for the centerpiece of what was once meant to be President Obama’s foreign policy “pivot” to Asia. As 2014 began, Japanese Prime Minister Shinzo Abe was promising to join the U.S.-led free-trade agreement as a spur to his own structural economic reforms. A bipartisan, bicameral group of senior U.S. lawmakers had agreed on a plan for “fast track” legislative authority to expedite a congressional vote on the TPP, once the 12 would-be members hammered out a final deal. Bucking resistance from trade skeptics in his own party, Mr. Obama had offered a friendly reference to that proposal in his State of the Union address on Jan. 28.

But Mr. Obama’s call was received coolly by Senate Majority Leader Harry Reid (D-Nev.) and by key Democratic constituencies such as organized labor. Foreign crises in the Middle East and Ukraine occupied the White House and Congress. Two champions of the bipartisan trade-promotion measure, Sen. Max Baucus (D-Mont.) and Rep. Dave Camp (R-Mich.), retired or planned to retire from Congress. For all of Mr. Abe’s talk of bold steps and confronting special interests in Japan, his negotiators have not yet backed up the prime minister’s talk with concrete proposals, even though the prime minister has said repeatedly that opening agricultural markets is in Japan’s interest. The upshot is that momentum behind the TPP seems to be flagging and the administration’s goal of a tentative agreement by the end of 2014 is looking less feasible.

Vice President Biden tried to patch things up with Mr. Abe in a meeting on Friday, which produced a boilerplate pledge to seek an agreement. It will take more than that to revive the momentum for the TPP and close a deal. Back home, Mr. Abe needs to keep the pressure on special interests. Congress could reciprocate by moving ahead promptly with fast-track authority during the post-election lame-duck period — which will take political courage on its part, too.