On the day he took office in 2001, President George W. Bush reversed twelve executive orders issued by Bill Clinton in his final weeks as president. Now, eight years later, Barack Obama is using the same tactic against Bush’s late regulatory changes. In the waning weeks of his presidency, Bush raced to put through an array of rules that included reversing a 25-year-old restriction on carrying loaded guns in national parks and restricting the input of government scientists in revising endangered species regulations. On Obama’s behalf, his chief of staff, Rahm Emanuel, sent out a memo halting the publication of any proposed regulation until it has been reviewed by the new administration, and asking that recently approved regulations not be enforced for 60 days.