Once again, lawmakers from both sides of the aisle are challenging the Obama administration over its national security policies. At issue now are secret legal opinions sanctioning the government’s targeted killing program, some of which were written by a Harvard law professor named David Barron, who is President Obama’s nominee for a prominent judicial position. At least two of the memos written by Barron when he worked in the Justice Department’s Office of Legal Council concern the extrajudicial killing of American citizens abroad.

Republican opposition to Barron is hardly surprising; much of it is simply the usual hysteria about his “progressive view of the constitution” that might lead him to wield his gavel “as a weapon to advance his hard-left political vision.” One exception is longtime drone critic Rand Paul, who has been threatening to hold up Barron’s confirmation due to his connection to the killing program. Paul penned a Sunday op-ed in The New York Times calling on the Obama administration to release the opinions drafted or signed by Barron before the Senate votes on his nomination.

A handful of Democrats, too, have expressed reservations about voting for Barron until they have a clearer view of his legal judgments on targeted strikes. The White House has given senators access to one of the Barron memos, which concerns the killing of US citizens overseas. In April, a federal judge ordered the administration to release that particular legal analysis not only to lawmakers but also to the public. It has not done so. Colorado Democrat Mark Udall told The New York Times that he would not support Barron’s nomination until the administration complies with the court order. Ron Wyden of Oregon said that the vote should not be held until more of Barron’s legal analyses are available.

Just how many memos related to drones Barron produced during his time at the Justice Department is unclear. (He worked at the OLC from 2009 to 2010.) Most of the controversy around Barron has focused on two memos, the one at the heart of the court case mentioned above, and a shorter one also reportedly related to targeting Americans. Those two documents were particularly pertinent in the decision to target an American named Anwar al-Awlaki, who died in a 2011 drone strike in Yemen. Interestingly, majority leader Harry Reid indicated on Tuesday that the White House has provided senators with a second memo, presumably the other one of the two. “As far as I know, they’re down there,” Reid said when asked if the proper documents were available in the secure area. “I’ve looked, there’s two of them.”

The killing of American citizens abroad without due process is a critical issue, but so is the policy of assassinating non-Americans away from the battlefield. Many other memos have been written about the drone program beyond its application to US citizens; it’s unclear whether Barron contributed to any of them. With the White House claiming it has given senators access to the information they’ve requested regarding the targeting of American citizens, the question of whether Barron analyzed any other aspects of the drone program may now become the focus of the debate.

“There’s been this game of ‘hide the ball’ that’s been going on for the last two weeks about what the White House is going to provide to the senators,” Christopher Anders, senior legislative counsel for the American Civil Liberties Union, said. “If they really have turned over everything he’s written regarding targeting killing, the White House should say that. Given the amount of games they’ve played, it certainly raises a lot of concerns that they’re sending up something less than all of the memos Barron has been involved in.”

Senator Dianne Feinstein, chair of the Intelligence Committee, has estimated that the OLC has produced at least eleven memos related to drone strikes, only four of which the Intelligence Committee has been given access to. That means there are at least seven legal opinions regarding the targeting killing program that no one in Congress has seen, though the National Security Act requires the executive branch to provide members of the intelligence committees with the information they request about intelligence activities.

Transparency at the OLC is in many ways a separate issue from Barron’s nomination. (Ironically, prior to his work in the Obama administration, Barron joined a group of legal scholars in signing a letter calling for greater openness from the office.) This is a point his supporters raise. “[Barron] has not advocated, much less ordered, the withholding of any documents,” Harvard law professors Charles Fried and Laurence Tribe wrote in in an op-ed for The Boston Globe on Tuesday.

Nevertheless, the withholding of the documents is directly related to the Senate’s ability to properly vet the nominee. That’s the case the ACLU made in a letter to senators last week, which Rand Paul quoted in his op-ed. “All senators should demand access to all opinions on the killing program written or signed by Mr. Barron,” the ACLU wrote (emphasis mine). “No senator can meaningfully carry out his or her constitutional obligation to provide ‘advice and consent’ on this nomination to a lifetime position as a federal appellate judge without being able to read Mr. Barron’s most important and consequential legal writing.”

It’s not clear how hard drone critics will push the White House to specify exactly how many memos Barron drafted. At Wednesday’s press briefing, press secretary Jay Carney said he didn’t know. Reid’s office did not return a request for comment about when he might schedule a confirmation vote for Barron, but he told reporters on Tuesday that he was “going to try to do it soon.” Still, it looks likely that for the second week in a row, the Senate will skip it.

With Barron in limbo, some on the left are debating whether holding up a vote is an effective means of encouraging greater transparency in the drone program. Groups like the NAACP and People for the American Way, eager for another Democratic appointment to balance the rightward tilt of the courts, have called on the Senate to move swiftly to confirm Barron. Judiciary Committee chair Patrick Leahy, though he applauded the White House’s decision last week to release one Barron memo to the full Senate, dismissed continued reluctance to the usual Republican games. “Senate Republicans have consistently blocked most of President Obama’s judicial nominees, so it comes as no surprise that they continue to do so with this nominee,” he said in a statement.

“I think it’s a real mistake to conflate the issue of whether David Barron should be a judge on the first circuit and the disclosure of the various memos that the OLC has written on the targeted killing program,” said Georgetown law professor David Cole, who just last year criticized the legal analysis supporting the targeting of Americans, which was laid out in a white paper leaked by the Justice Department. Cole sees the issue as a “red herring” for Republicans who are opposed to Barron for ideological reasons, and he criticized liberal groups for using Barron “as a sacrificial leverage point to get the documents disclosed.”