Five years ago, Mexico was a classic example of everything wrong in the developing world: The country's centrally planned economy had collapsed, political leadership was wanting and government inefficiency and corruption were rampant. Many Mexicans believed their country would never recover. Now, suddenly, Mexico has emerged as one of the world's most promising economies. Carlos Salinas de Gortari, Mexico's 43-year-old president, has embarked on a bold course toward modernization. By opening up the economy and proposing a free-trade agreement with the United States, he hopes to lure foreign investment and liberate his impoverished country from decades of underdevelopment. In the process, he is altering the nature of U.S.-Mexican relations. He is also creating pressures for political change.