Steamy Iquitos, Peru's chief Amazon River port, was sleeping under a velvet equatorial sky when military boots first began to scrape along the streets. Tough little soldiers in suntans deployed briskly. In less than an hour, without firing a shot, they occupied the city's radio stations, telegraph office, and the big, grey prefectura building, Capitol of the jungled, Arizona-size department of Loreto.
Soon after sunup the rest of the garrison was standing at attention in the treelined Plaza de Armas. Brigadier General Marcial Merino Pereyra, their commander, read off a manifesto explaining to his men why he had led them into...