The person to watch in American medical science today is a California real estate developer named Robert Klein II. As the driving force behind the initiative to invest $3 billion in stem cell research over the next decade, the builder-financier has just been nominated by Gov. Arnold Schwarzenegger to head the citizens' committee overseeing the state's Institute for Regenerative Medicine. Here we have federalism in action, with states competing to lead the central government in creating national policy. When the government in Washington decided to move cautiously in funding this promising but controversial scientific research, individual states saw the competitive...