THE TRANS-PACIFIC Partnership has been described as the centerpiece of President Obama’s attempt to “pivot” U.S. foreign policy toward Asia, and with good reason. A proposed trade liberalization agreement among 12 nations, the TPP would, in binding the United States more closely with a portion of the world, collectively account for 40 percent of global output. At the same time, it would ensure that this huge area, including giants such as Japan, Canada, Mexico and Australia, conducts business according to U.S.-style rules on tariffs, regulation and intellectual property. China would be left on the sidelines, along with its mercantilist model of international commerce — unless and until it modifies that approach. The net effect would be a better balance of power, money and ideas between the United States and its allies on the one hand and China on the other.

To reap these strategic benefits, of course, the United States and the other 11 would-be members of the TPP must first cut a deal. As a practical matter, that means everyone is waiting for a “yes” between Washington and Tokyo, the two biggest economies in the group, and the two with the most divergent approaches, historically, to trade. When Japanese Prime Minister Shinzo Abe agreed last year to pursue a TPP deal , he seemed to be making an historic decision to open his country’s long-closed domestic markets — not only to satisfy long-standing U.S. complaints about Japanese protectionism but also to subject Japan’s stagnant economy to the bracing effects of competition. Lately, however, talks have stalled over age-old issues such as Japan’s high tariffs on U.S. meat and its non-tariff barriers (regulations and such) against U.S. autos.

Now, as President Obama embarks on an Asian trip, the highlight of which will be a state visit to Japan, pessimism about the two countries’ ability to reach a TPP deal is growing. Japan alone is not to blame: Congress has failed to grant Mr. Obama “fast-track” authority to speed lawmakers’ approval of a deal once it’s negotiated. That ostensible sign of flagging U.S. interest weakened the U.S. negotiating team’s position and reinforced deep-seated resistance to trade liberalization among Japan’s political interest groups.

Mr. Obama and Mr. Abe must use this state visit to shore up U.S.-Japan relations and to refocus their respective publics on what’s really at stake. The world remains fraught with geopolitical risks. China’s rise is not the only danger — as Russian President Vladi­mir Putin’s seizure of Crimea has shown. Among the best safeguards against these risks are the United States’ traditional alliances such as NATO and the 50-year-old mutual-defense pact that has bound the United States and Japan . The Trans-Pacific Partnership would augment and update that long-standing partnership.

Trade specialists from the respective countries can haggle forever about how many U.S. pork bellies get to enter Tokyo. And they might do just that, unless their leaders make it crystal clear that the time has come for compromise in both countries’ higher economic and strategic interest. This week’s meeting is a golden opportunity to send that message.