Earlier this year, both The New York Times and The Washington Post confirmed that the Obama administration authorized the CIA to kill American-born, Yemeni-based Islamic cleric, Anwar al-Awlaki.

Several people I admire and respect—and who are far more versed in the legal aspects of the “war on terror”—have already weighed in on whether the U.S. Government is authorized to kill U.S. terror suspects abroad, so I defer to those experts.

But what’s interesting is that the U.S. Government has killed “many Westerners, including some U.S. passport holders” in Pakistan’s tribal areas dating all the way back to the Bush administration, according to Bob Woodward’s new book.

Jeff Stein over at WaPo’s SpyTalk writes that according to Woodward, on November 12, 2008, then-CIA Director Gen. Michael Hayden disclosed the killings to Pakistani president Asif Ali Zardari during a meeting in New York. At the meeting, Zardari allegedly said, “Collateral damage worries you Americans. It does not worry me.”

It now appears that two human rights groups are challenging the legality of the Obama Justice Department’s right to kill U.S. citizens abroad. Will these groups now do the same with former Bush officials, too?