Opponents of the deal argue that it doesn't go far enough to "get tough" with trading partners seen as taking unfair advantage of existing trade deals.
But supporters predict that by lowering trade barriers, the partners would boost exports by nearly half a trillion dollars by 2030, when the deal was set to be fully in place, according to a report from the Peterson Institute for International Economics.
Japan would be one of the biggest beneficiaries of the deal, generating $125 billion in additional income by 2030, adding another 2.5 percent to GDP, the report said.
In the United States, boosting TPP partner exports would add 0.5 percent of GDP, with annual exports rising by $357 billion, or 9.1 percent of exports, by 2030.
With the TPP now all but dead in Congress, Japan and the other partners in the deal may benefit from the proposed Regional Comprehensive Economic Partnership, or RECP, an alternate trade deal that includes China and 15 other Asian countries.
Those countries include a larger share of Japanese exports, which could offer some relief from the failures of the TPP.
But Japan already has free trade agreements with most of the RCEP countries, according to Capital Economics economist Marcel Thieliant.
"The demise of the TPP will still do lasting harm to Japan's long-term prospects even if the RCEP comes into force," he wrote in a note to clients.