Strictly speaking, Eric Holder already acknowledged this yesterday after three agonizing minutes of Ted Cruz teasing it out of him. But Rand Paul wanted a formal statement from the White House as a condition of ending his filibuster. And now, apparently, he’s got it:

White House spokesman Jay Carney told reporters at 1:15 pm. that Mr. Holder’s letter to the Kentucky Republican went out shortly after noon, and just 12 hours after Mr. Paul stages a marathon talking filibuster on the Senate floor demanding clarification of U.S. drone policies and the president’s authority to order strikes on Americans.

Mr. Holder’s letter answers Mr. Rand’s question, “Does the president have the authority to use a weaponized drone to kill Americans not engaged in combat on U.S. soil,” Mr. Carney said.

“The answer to that question is no,” he said. “A letter signed by the attorney general has gone out in the last half an hour.”

That’s nearly the full text of the letter, a copy of which you can find at the Weekly Standard. All that’s missing is how it begins: “It has come to my attention that you have now asked an additional question.” Yeah? Paul’s been demanding an answer from the White House about this since mid-February at least. Only yesterday, after he spent 13 hours on the Senate floor repeating that question a few thousand times, did it finally come to Holder’s attention?

Also, before you celebrate, think carefully about whether Holder’s really answering his concerns. Paul wasn’t just asking about “weaponized drones.” He was asking about targeted killing generally. Sending the CIA in to shoot a guy in the head because he’s on O’s “kill list” doesn’t address the due process concerns just because no drone was used. The phrase “not engaged in combat” is also murky since the entire point of this debate is about defining what it means to be “engaged in combat” against the United States. Paul’s point yesterday was that, even if a U.S. citizen is an “enemy combatant,” the feds should be barred from summarily executing him if he’s on U.S. soil. Only if he’s in the process of carrying out an attack is lethal force justified. That’s his definition of “engaged in combat,” at least inside the continental U.S. The alternate definition is that an “enemy combatant” is, by his very nature, always engaged in combat against America. The DOJ itself more or less adopted that definition by defining “imminence” so broadly in its “white paper” on drone attacks as to suggest that members of Al Qaeda are always, at every moment, posing an imminent threat because they’re “continually plotting.” By that standard, Obama could drop a bomb on a U.S.-born jihadi hiding in an American safe house and still be okay under Holder’s letter here because the target was, as a member of Al Qaeda who was up to no good, necessarily “engaged in combat.” We’ll see what Paul has to say to all this. Not sure if he’s seen the letter yet, but for now he’s enjoying seeing them forced to speak up:

Rand Paul doing an end zone dance on Fox: "Under duress, and under public humiliation, the White House will relent and do the right thing."

— Mike O'Brien (@mpoindc) March 7, 2013

Update: Perhaps it’s time for Congress to stop letting Obama define his own authority on this:

We suspect the day an administration starts killing Americans with drones at cafes — to borrow one of Rand Paul’s hypotheticals — is the day impeachment proceedings begin. If Congress is worried, though, there is a simple expedient. As Andy McCarthy has written, “Nothing prevents Congress from amending the AUMF to provide explicit protections for Americans suspected of colluding with this unique enemy. Congress could, for example, instruct that in the absence of an attack or a truly imminent threat, the president is not authorized to use lethal force in the United States against Americans suspected of being enemy combatants. Congress could also define what it means by ‘imminent.’”

And in fact, Paul and Ted Cruz have a bill in the works that would do just that. Which poses a dilemma for O: Resist on grounds that the bill is a violation of separation of powers because it circumscribes his authority as commander-in-chief, or give in because it would be simply atrocious for a president to oppose a bill limiting his power to assassinate Americans?

Update: Paul says he’s A-OK with Holder’s response:

“I’m quite happy with the answer,” Paul told CNN. “Through the advise and consent process, I’ve got an important answer.”