According to Aid, the White House's rejection of Blair's attempt to bring the appointment of station chiefs under the DNI's authority soured Blair's relationships with Panetta, despite a long personal friendship between the two, and Obama's Homeland Security Advisor, John Brennan, who had sided with Panetta in the dispute (Brennan later succeeded Panetta as Director of the CIA). When it was discovered that the November 2009 Fort Hood shooting and the attempted bombing of Northwest Airlines Flight 253 a month later could have been prevented with better inter-agency intelligence sharing, Brennan and Panetta allegedly blamed Blair (which, according to Aid, was not justified), resulting in Obama's decision to replace him.