Approximately 250 holdovers from the Bush administration at the Defense Department had until yesterday to sign President Barack Obama’s ethics pledge, or pack their bags, according to an internal memo issued on Tuesday. In December, the incoming president asked many of the Bush appointees to stay on past the inauguration to help maintain continuity. But for those wishing to stick around longer, they would have to sign the pledge, which grew out of the executive order Obama signed right after taking office. The pledge seeks to close the so-called “revolving door” between the Defense Department and military contractors that critics insist creates numerous and serious conflicts of interest.