Barr previously held this position from 1991 to 1993 under former president George H. W. Bush, after raising through the ranks of the Justice Department following his work at the CIA. Since then, he’s held various positions in law firms and companies like Verizon.

While he has ample support from Republican leaders, Barr is likely to be scrutinized by Democrats hoping to ensure the protection of Special Counsel Robert Mueller’s investigation. Trump’s last attorney general, Jeff Sessions, recused himself from oversight of that investigation, angering the president who had hoped for a loyalist in the Justice Department. Sessions has since stepped down, replaced on an interim basis by Matthew Whitaker, a harsh critic of the Mueller investigation.

Barr’s history has some—like former Attorney General John Ashcroft—saying he would easily gain bipartisan support. Others, however, will have some questions about Barr’s past, including his support for stronger protections of the president’s executive power—a viewpoint that Trump would likely approve.

On the other hand, Barr also distanced himself from the executive branch in a 1992 speech in which he addressed the need for an attorney general’s allegiance to the law.

“The attorney general’s oath to uphold the Constitution raises the question whether his duty lies ultimately with the president who appointed him or more abstractly with the rule of law,” Barr said at the time, according to the The New York Times. “I said in my confirmation hearings, and have said several times since, that the attorney general’s ultimate allegiance must be to the rule of law.”

This stance came forward earlier this year, following Sessions’ recusal from the Russia investigation. Barr defended the decision, saying it showed integrity.

On the whole, however, Barr has historically sided with the president. He told The New York Times last year that the Justice Department was “abdicating its responsibility” by investigating Trump’s possible collusion with Russia instead of looking into other subjects, such as the Clinton-Uranium One deal.

The American Civil Liberties Union voiced concerns over Barr’s viewpoints Friday, saying his past “suggests that he will follow Jeff Sessions’ legacy of hostility to civil rights and civil liberties.”

“Barr must commit to defending the rule of law and civil rights, not serving as a political arm of Trump’s anti-constitutional agenda,” Faiz Shakir, the ACLU national political director, said in a statement.

Barr has also defended Trump’s firing of former FBI Director James Comey (although only if the decision was unrelated to the Russia investigation), and questioned whether Mueller’s team included too many people who donated to Democrats.

These subjects are likely to come into question when Barr goes through Senate confirmation, but such hearings are unlikely to take place until the new session begins after the new year.

Sen. Lindsey Graham (R-SC), future chairman of the Senate Judiciary Committee, said, “I will do everything in my power to push him through the Senate Judiciary Committee and onto the floor of the Senate for eventual confirmation as soon as possible.”