In 2009, Dianne Feinstein (D-Calif.) became the first woman to lead the storied Senate Select Committee on Intelligence — just as Barack Obama became the second president to oversee the massively expanded national security establishment that America developed after the 9/11 terror attacks.Both Democrats had condemned the way President George W. Bush handled security matters,and both particularly opposed the Bush administration’s use of a global detention and interrogation program for suspected terrorists. Feinstein, who died on Friday at age 90, channeled that concern into a yearslong battle, defying opponents ranging from Obama’s team to the CIA and its allies. The result was a lasting statement against torture and in favor of accountability. Feinstein’s unlikely push to reveal the truth...