Liberals are being forced to deal with the cognitive dissonance conjured by the inconvenient truth that Mr. Bush freed al-Shiri from detention and Mr. Obama hunted him down and killed him. We support the targeted killing program because it is the only aspect of Mr. Obama's national security strategy that is reaping concrete benefits. The "blame Bush" mantra, however, is simply a way for Mr. Obama's left-wing supporters to avoid asking hard questions about the future of terrorist detainees. Meanwhile, potential reinforcements continue to flow to the region under the president's detainee-release program. On Dec. 20, six Yemenis arrived in...