The following editorial appeared in the Los Angeles Times on Friday, March 8:

Sen. Rand Paul, R-Ky., waged a 13-hour filibuster on the Senate floor this week in a futile effort to set clear limits on the administration’s use of covert military force. Specifically, Paul wanted the administration to concede that it couldn’t legally assassinate Americans on U.S. soil. The idea that a president would approve a drone strike on a citizen sitting at a cafe in Boston or San Francisco or Wichita seems far-fetched, but even the least paranoid among us can’t help but be troubled by the administration’s less-than-definitive assurances.

We have repeatedly expressed concern about the administration’s open-ended approach to targeted assassinations around the world. This week’s discussion shows again that the United States is sliding down a slippery slope, with the government gaining power to head off potential attacks at the expense of individual rights. And it’s not at all clear where it will stop.

Paul’s protest on Wednesday was ostensibly aimed at President Obama’s nominee for CIA director, John Brennan. As the president’s top counter-terrorism adviser, Brennan has been an architect of the drone strikes that have killed hundreds of alleged enemy combatants and al-Qaida operatives overseas, including a handful of American citizens.

Paul couldn’t hope to stop Brennan’s ascension; the Senate confirmed him Thursday by a vote of 63 to 34. Instead, Paul commandeered the Senate floor to shine a spotlight on Obama’s and President George W. Bush’s expansive approaches to combating terrorism. As we have warned repeatedly, these presidents have claimed far-reaching authority to summarily execute people they deem a threat to homeland security, with little or no oversight over whom they target or where they carry out the killings.

Paul took the White House’s position to an absurd extreme in arguing that vocal government critics could be targeted for drone strikes in this country. But the fact remains that the administration has steadily increased the use of drones, widened the definition of an “imminent” threat and expanded the boundaries of the “battlefield” where they can be used.

Attorney General Eric H. Holder Jr. tried to dispel concerns in letters to Paul on Monday and on Thursday, when he flatly declared that the president does not have the authority to use a drone to kill a citizen “not engaged in combat” here in the United States. But just as the Obama administration has stretched the meaning of “imminent” to cover situations in which there’s no evidence of a looming attack, so could future attorneys general interpret “combat” as something other than actively trying to kill Americans.

Sen. Dianne Feinstein, D-Calif., chairwoman of the Senate Intelligence Committee, declared that Paul’s nightmare scenario of a citizen being assassinated in a cafe “will never happen in the United States of America.” That’s because, in Feinstein’s mind, there’s a clear distinction between enemy combatants overseas who easily elude capture and plotters in the United States who can be tracked and arrested. But the last two administrations have blurred the line separating crimes from acts of war. And even if you trust Obama’s judgment, do you want to grant the same discretion to his successors, whoever they might be?