ATLANTA, Ga. — Investigators blame last month’s deadly Atlanta courthouse shooting on a series of mistakes and missteps. But some affirmative action critics say it boils down to the fact that there was a woman deputy escorting accused gunman Brian Nichols. “You have a female officer who is about 5 feet 2 inches tall, versus a criminal in this case — a former linebacker who is 6 feet tall,” said John Lott, a resident scholar at the American Enterprise Institute, a think tank in Washington. Those in favor of affirmative action — the policy of hiring and recruiting with the...