The United States, Japan, Canada, Vietnam and eight other nations have been working on the proposed Trans-Pacific Partnership for years, and were hoping to wrap up an agreement during this week's negotiations in Atlanta.
The issues include Washington's push to extend patent protection on a promising new class of drugs for longer than other nations want. Other disputes include dairy exporter New Zealand seeking greater access to Canada's dairy market, and squabbles between the United States and Japan over auto industry trade.
Resolving these and other disputes is made more difficult by pending elections in several key nations, where some workers and farmers worry that increased trade will mean decreased employment. Many businesses support expanded trade as a way to open new markets to exports.