Trade pact would be a bonanza for Africa — if it can be made to work

The United States, Mexico and Canada trade with one another under a pact that replaced the long-standing North American Free Trade Agreement, or NAFTA. The Europeans have their single market and common currency. Southeast Asian countries have a free-trade agreement. And 11 Pacific Rim countries have formed their own free-trade group with the unwieldy acronym CPTPP.