By SEATTLE - When President Bush plunged into the debate over the teaching of evolution this month, saying, "both sides ought to be properly taught," he seemed to be reading from the playbook of the Discovery Institute, the conservative think tank here that is at the helm of this newly volatile frontier in the nation's culture wars. After toiling in obscurity for nearly a decade, the institute's Center for Science and Culture has emerged in recent months as the ideological and strategic backbone behind the eruption of skirmishes over science in school districts and state capitals across the country. Pushing...