Would law professor or senator Barack Obama have supported effectively giving a U.S. president unilateral power to kill American citizens abroad if they are suspected of being involved in terrorism?

The controversy over an Obama administration memo, first obtained by NBC News, that describes the administration’s legal justification for killing even U.S. citizens, gets at a core question of the president’s anti-terrorism policies: would Democrats, even Obama himself, have been comfortable with George W. Bush taking similar approaches? (Many, even at times Obama, were not, although the specific issue of U.S. citizens is new.) Would they support a president Jindal or Rubio or Jeb Bush if he asserted such executive authority?

“Even if the Obama administration is convinced of its own fundamental trustworthiness, the power this white paper sets out will be available to every future president—and every “informed high-level official” (!)—in every future conflict,” wrote Jameel Jaffer, deputy director of the American Civil Liberties Union, on the organization’s website after the disclosure of the memo.

At the core, the administration’s use of drone strikes to kill suspected al-Qa’ida operatives, both U.S. citizens and non-citizens, hands the president and his team almost total power in determining if a person is connected to terrorism and therefore if the U.S. should use military force to kill them. There is almost no opportunity for any kind of review by the judiciary or Congress.

Obama’s approach isn’t much different from George W. Bush’s, but Democrats spent years casting Bush and Vice-President Dick Cheney as holding an overly-expansive view of executive power.

This debate will get perhaps its most public airing on Thursday, when John Brennan, Obama’s top counter-terrorism adviser and a key architect of the drone program, will answer questions at a Senate hearing on his nomination to direct the CIA.  Members of both parties are likely to ask about this memo and what limits, if any, it imposes not only on Obama, but also future presidents.

Follow Perry Bacon Jr. on Twitter at @PerryBaconJr.