WASHINGTON — A far-reaching trade pact binding a dozen Pacific Rim nations would increase incomes, exports and growth in the United States but is unlikely to add to overall employment, according to an independent analysis released Monday.

The Trans-Pacific Partnership, President Obama’s biggest economic priority of his final year in office, would not cost overall employment either, the report said, but inevitably some work, especially in manufacturing, would be lost even as export-industry jobs are created — a downside that political opponents in Congress and in both parties’ presidential races have been emphasizing for months.

The pact would liberalize trade from Canada to Chile and Australia to Japan. Other parties to the accord are Mexico, Peru, New Zealand, Singapore, Malaysia, Vietnam and Brunei.

The Obama administration quickly endorsed the analysis from the Washington-based Peterson Institute for International Economics to buttress its uphill fight for Congress’s approval of the Trans-Pacific Partnership, completed last October after years of negotiations. An earlier analysis for the World Bank likewise underscored the regional as well as global benefits of the accord, if ratified. Yet both organizations, as champions of international trade, are unlikely to sway the skeptics at a time of widespread economic uncertainty for many American workers.