With some measure of disappointment, conservatives are talking about Secretary Condoleezza Rice's propensity to award key State Department slots to career Foreign Service operatives rather than outsiders. The latest of Rice's key associates to come from the career service are Nicholas Burns, onetime State Department spokesman under Jimmy Carter, who will be under secretary of State for political affairs and C. David Welch, formerly U.S. ambassador to Egypt, who will be assistant secretary of State for Near Eastern Affairs.