DEL MAR, CA - A swing through the course of American Thoroughbred history yields the widely-accepted conclusion that dirt plays the king in these parts, while turf is the patient understudy offstage left--turns are configured in that direction over here. It was not all that long ago that droves of U.S. tracks debated whether putting in a bladed surface and acquiring something called a going stick made any sense. Progressive places like Del Mar's Thoroughbred Club damned the salt in the marine layer and forged ahead with its first course...