MONTERREY, Mexico - Nowhere was the political earthquake that jolted Mexico's ruling Institutional Revolutionary Party (PRI) a week ago felt more keenly than in the prosperous northern industrial state of Nuevo Leon.
Not only did the conservative National Action Party (PAN) take the governorship from the PRI for the first time, it captured 19 of the 26 seats in the state legislature, elected nine of the state's 11 members of the lower house of Congress and held the municipal governments of Monterrey and four of its suburbs, which it captured three years ago.
The sweeping victory could spell trouble for the PRI going into the presidential election in 2000. The northern tier of states, where export-focused assembly plants have generated jobs, has voted increasingly for the PAN. Two other border states, Chihuahua and Baja California Norte, have PAN governors.
The North American Free Trade Agreement has spurred a northern economic boom that has benefited the middle-class-based PAN. West Virginia-sized Nuevo Leon's wealth gives it political clout out of proportion to its population of 3.3 million.
Monterrey, the state capital and Mexico's third-largest city, has long enjoyed a standard of living higher than most other Mexican cities. Absent is the guerrilla activity that plagues such destitute southern states as Chiapas and Guerrero.
The left-wing Party of the Democratic Revolution (PRD), which handily won the Mexico City mayor's race, is a negligible force here.
The PAN landslide in Nuevo Leon exceeded even the party's optimistic forecast. Julio Castrillon, a successful candidate for Congress, had predicted the party would win six or seven of the 11 seats. Before the election, the PRI held nine and the PAN had two.
"This is the death of the one-party system," Mr. Castrillon said in an interview. "It is a historic turnover. The decisions in the Congress will have to be by consensus. …