Senate Intelligence Committee members are closely guarding how they might vote on the nomination of John O. Brennan to lead the CIA, but one thing is for sure: He will catch heat from Democrats and Republicans alike at his confirmation hearing Thursday.

That would make Brennan’s nomination hearing different in tone from the relatively peaceful nomination hearings of President Barack Obama’s two previous CIA directors, Leon E. Panetta and David H. Petraeus.

As a longtime CIA official and the top White House counterterrorism and homeland security adviser to Obama, Brennan has been at the center of, or at least near, debates about some of the country’s most controversial post-Sept. 11, 2001, national security policies. Panetta had been out of government prior to getting picked for the CIA post, while Petraeus was popular enough with lawmakers on both sides of the aisle as to make him virtually bulletproof at his nomination hearing.

One Democrat, Ron Wyden of Oregon, has indicated he plans to ask Brennan about the Obama administration’s drone strike program, particularly the targeted killing of U.S. citizens suspected of terrorism. Two Democrats, panel Chairwoman Dianne Feinstein of California and Mark Udall of Colorado, also plan to ask about his views on the committee’s recently completed report on the detention and interrogation practices. Feinstein has praised the pick of Brennan, but Udall recently issued an angry news release about Brennan not answering his questions about the report during his meeting with the nominee.

At least one Republican member, Susan Collins of Maine, has also expressed interest in the issue of drone strikes, but multiple GOP members — Dan Coats of Indiana and Marco Rubio of Florida — have indicated their focus is on the Obama administration’s record of national security leaks. And a Senate aide added that “Republicans will want to ask about his conflicting positions on the CIA interrogation program and his role in various leaks.”

Every nomination hearing has the potential to make or break a nominee, but given the many trouble spots for Brennan, the hearing could be even more pivotal. The Intelligence Committee is divided more narrowly than most, with eight Democrat and seven Republicans.

The Senate aide speculated that if Brennan does not “do a good job assuaging the Dems about his views, I think he’ll have problems. I think Republicans are interested in how he answers their questions on Thursday and will base their vote on his responses and the administration’s willingness to provide information they have requested.” The aide also noted that Brennan is not a former Senate colleague like other Obama national security-related nominees John Kerry, who was sworn in Friday as secretary of State, or Chuck Hagel, who is fighting to be confirmed as Pentagon chief.

If Brennan makes it through the committee, he could still face difficulty advancing elsewhere.

Lindsey Graham, R-S.C., has threatened to hold up his nomination over information he’s demanding from the administration about the Sept., 2012 attack on the U.S. consulate in Benghazi, Libya, while Wyden has not ruled out a hold if he doesn’t get the legal memos he is seeking about targeted killings of U.S. citizens. On Tuesday, Attorney General Eric H. Holder said that releasing more information would jeopardize intelligence sources and methods.

Wyden said Tuesday he would ask several questions about drones that a recently disclosed Justice Department white paper about the targeted killing policy does not answer.

“The Justice Department memo that was made public yesterday touches on a number of important issues, but it leaves many of the most important questions about the President’s lethal authorities unanswered,” Wyden said. “Questions like ‘how much evidence does the president need to decide that a particular American is part of a terrorist group?,’ ‘does the president have to provide individual Americans with the opportunity to surrender?’ and ‘can the president order intelligence agencies or the military to kill an American who is inside the United States?’ need to be asked and answered in a way that is consistent with American laws and American values.”

Wyden, Udall and Collins all signed a letter this week to the president asking for the Office of Legal Counsel memos pertaining to the drone strike program, in which Brennan has played a leading role.

Coats, who said he was undecided on Brennan and has some issues that will have to be discussed in a closed hearing, had a “positive” meeting with Brennan one on one.

“The biggest issue I’ve had is this whole question of leaks. We had a whole series of these in the spring and the summer, and I want to be sure we have his full 100 percent positive support to do everything possible to keep this from happening,” Coats said.

That’s a concern shared by Rubio.

“We have a process for nominations, and Senator Rubio won’t prejudge the nominees,” said his spokeswoman, Brooke Sammon. “The national security leaks during President Obama’s first term were worrisome and should be a topic for Mr. Brennan’s nomination hearing. As a member of the Intelligence Committee, Sen. Rubio looks forward to engaging Mr. Brennan during this process.”

A number of committee members, including the panel’s vice chairman, Saxby Chambliss, R-Ga., Jim Risch, R-Idaho, Tom Coburn, R-Okla., said this week that they will not comment on Brennan’s nomination at all until the hearing, although Chambliss has said he has unspecified concerns about Obama’s pick.

Udall, who was upset after his meeting with Brennan that the nominee had not yet read the Intelligence Committee’s report on interrogation practices, said his first opportunity to discuss the issue again with Brennan is Thursday’s hearing. “It’s important,” Udall said. “I’m looking forward to him coming and telling us what he’s learned.”

Chris Anders, legislative counsel for the American Civil Liberties Union, said he has spoken to Republicans who also have been miffed at Brennan for refusing to answer questions dating from before his nomination. Given the concerns about Brennan from both Democrats and Republicans, some of which are shared, Anders said it could be a rocky hearing Thursday.

“It all adds up to a much more difficult nomination that the White House thought it would be,” he said. “I think it’s going to be a wild day for them.”

Jay Carney, White House spokesman, said Tuesday that the president believes Brennan will be confirmed.