Corruption on the Border Intrigue and chaos in Tijuana TWILIGHT ON THE LINE Underworlds and Politice at the US.-Mexican Border By Sebastian Botelia W.W. Norton; 320 pages; $25 On California's southern frontier drug cmuggling has become a multibillion-dollar business, corrupting officials on both sides of the border and spawning violence that has severely destabilized the Mexican government. It's heady material for a writer, and Los Angeles Times reporter Sebastian Rotella rises to the occasion. In "Twilight on the Line" he exhaustively and eloquently describes the intrigue and chaos of the area on and around Tijuana, Mexico. [continues 689 words]