Ed Reinke, AP
The dispute between Paul and Holder began over a controversial Justice Department white paper leaked in early February that left civil libertarians flustered as to the rules on how lethal force might be used against American citizens.

After holding the Senate floor for 13 hours in a rare old-fashioned filibuster on Wednesday, Sen. Rand Paul, R-Ken., got what he wanted: a clear statement from Attorney General Eric Holder that drones could not legally be used to kill Americans not engaged in combat and on American soil.

"I've kind of won my battle," Paul told The Washington Post after getting Holder’s letter on Thursday, which ended Paul's filibuster of John Brennan's nomination to head the CIA.

The Wall Street Journal editors were less impressed, urging Paul to “calm down” and calling the filibuster a “political stunt” aimed to “fire up impressionable libertarian kids in their college dorms.”

Utah Sen. Mike Lee, also a Republican, was one of handful of senators who actively backed Paul’s filibuster. Others included one Democrat, Sen. Ron Wyden of Oregon, and Republican tea party favorites Ted Cruz of Texas and Marco Rubio of Florida.

And late in the day Paul got a big push from Senate Minority Leader Mitch McConnell, R-Ken., who said he would "congratulate my colleague from Kentucky for this extraordinary effort.”

Thursday afternoon, with the filibuster settled and Brennan confirmed at the CIA, Lee got on the phone with the Deseret News, calling Paul’s filibuster a “significant victory.”

The dispute between Paul and Holder began over a controversial Justice Department white paper leaked in early February that left civil libertarians flustered as to the rules on how lethal force might be used against American citizens.

As part of Brennan’s confirmation process, Paul pressed Brennan repeatedly for clarification on key points, including whether he believed the executive branch had authority to order an extrajudicial killing of an American citizen on American soil.

The subsequent response from Holder, critics argued, only raised further questions.

"The question you have posed is therefore entirely hypothetical, unlikely to occur, and one we hope no President will ever have to confront," Holder wrote.

"It is possible, I suppose, to imagine an extraordinary circumstance in which it would be necessary and appropriate for the President to authorize the military to use lethal force within the territory of the United States."

Paul’s stated objective with the filibuster was to force the administration to clarify Holder’s hypothetical musing.

On Friday morning, Holder responded to Paul’s filibuster with a three sentence letter. “It has come to my attention that you have now asked an additional question,” Holder wrote. “'Does the President have the authority to use a weaponized drone to kill an American not engaged in combat on American soil?' The answer to that question is no.”

The Wall Street Journal editors, however, insisted the law was always clear on this point, however muddled the attorney general may have left it.

“The U.S. government cannot randomly target American citizens on U.S. soil or anywhere else,” the editorial read. “What it can do under the laws of war is target an 'enemy combatant' anywhere at anytime, including on U.S. soil. This includes a U.S. citizen who is also an enemy combatant. The President can designate such a combatant if he belongs to an entity — a government, say, or a terrorist network like al Qaeda — that has taken up arms against the United States as part of an internationally recognized armed conflict.”

Lee was puzzled, given the brevity and simplicity of Holder's letter on Thursday, that there was so much resistance to making the statement.

"The fact that it took that much effort to get such a benign statement was itself disconcerting," Lee said. "These are pretty simple principles. This should not be controversial."

Paul was not the only senator to latch onto this issue. Weeks earlier Wyden, the Oregon Democrat, wrote Brennan after his nomination to the CIA post, pressing for detail on guidelines that would control a decision to kill an American citizen.

"For the executive branch to claim that intelligence agencies have authority to knowingly kill American citizens," Wyden wrote, "but refuse to provide Congress with any and all legal opinions that explain the executive branch's understanding of this authority, represents an alarming and indefensible assertion of executive prerogative."

"I have great respect for Ron Wyden," Lee said. "I appreciate his willingness to stand on principle. Ron Wyden has been an ally not only in this area but in other areas dealing with individual liberties."

Some of Paul's GOP colleagues were not pleased with Paul’s filibuster, including Sens. Lindsey Graham of South Carolina and John McCain of Arizona. Taking to the Senate floor Thursday, Graham said he had no worries about the president attacking Americans.

“Here’s what I worry about," Graham said, "that al-Qaeda has killed 2,958 of us and is going to add to the total if we let our guard down. And I will do everything in my power to protect this president — who I disagree with a lot — and future presidents in having an ill-informed Congress take over the legitimate authority under the Constitution and the laws of this land to be the commander-in-chief on behalf of all of us.”

Lee said he was surprised at McCain's and Graham's posture, given how "most senators and most Republican senators have expressed great respect for what Rand Paul was doing."

Lee knows that many have questioned the sincerity of conservative Republicans challenging the executive branch on civil liberty grounds, but he argues that this only reflects ignorance of what drives the tea party wing of the GOP.

"This is what the tea party movement is,” Lee said. “The tea party is all about constitutionally limited government. That has implications not just in economics. We also want to limit government’s capacity to harm us in other areas. We believe in individual liberties, in God-given rights that the government can't infringe."

Eric Schulzke writes on national politics for the Deseret News. He can be contacted at eschulzke@desnews.com.