WASHINGTON (Reuters) - Brett Kavanaugh, President Donald Trump’s U.S. Supreme Court nominee, embraced judicial independence on Wednesday but sidestepped Senate Democrats’ questions on whether a president can pardon himself or fire a prosecutor investigating him.

Kavanaugh faced a grueling session of more than 12 hours of questioning before a Senate panel that was disrupted repeatedly by shouting protesters. Senators pressed the conservative federal appeals court judge on his views about presidential power, abortion, gun rights and race issues.

All four issues deeply divide Americans and could come before the Supreme Court, with Kavanaugh likely to tip the court in an even more conservative direction.

Kavanaugh signaled respect for the landmark 1973 Roe v. Wade Supreme Court ruling legalizing abortion nationwide, calling it an important legal precedent that had been reaffirmed by the justices over the decades.

He condemned the spate of U.S. school shootings but defended an opinion he wrote questioning whether semi-automatic rifles could be banned. He also defended his record on race issues.

Senate Democrats have vowed a fierce fight to block Kavanaugh’s nomination. However, with Trump’s fellow Republicans holding a slim Senate majority and no sign of defections in Republican ranks, it remains likely Kavanaugh will be confirmed to the lifetime job on the top U.S. judicial body.

With Trump’s presidency clouded by a widening probe into Russian election meddling, Kavanaugh declined to pledge to step aside from any cases that might come before the court involving Trump’s conduct.

Kavanaugh said in reply to a question from Democratic Senator Richard Blumenthal he could not commit to recusing himself from any cases involving investigations or civil lawsuits relating to the president.

“To be consistent with the principle of the independence of the judiciary, I should not and may not make a commitment about how I would handle a particular case,” Kavanaugh said.

Trump has often criticized the judiciary. Some liberals have expressed concern Kavanaugh could be a rubber stamp for Trump and protect him from lawsuits and investigations.

Asked by Judiciary Committee Chairman Chuck Grassley, a Republican, whether he would have any trouble ruling against Trump or the executive branch, Kavanaugh replied: “No one is above the law in our constitutional system.”

“I think the first quality of a good judge in our constitutional system is independence,” Kavanaugh said.

PRESIDENTIAL POWER

Kavanaugh dodged Democratic Senator Dianne Feinstein’s question about whether a sitting president can “be required to respond to a subpoena,” a query that could come into play as Special Counsel Robert Mueller investigates potential collusion between Trump’s 2016 presidential campaign and Russia.

“I can’t give you an answer on that hypothetical question,” Kavanaugh said.

He sidestepped Democratic Senator Christopher Coons’ query on whether he still believed, as he wrote 20 years ago, that a president could fire a special prosecutor investigating him. “All I can say is that was my view in 1998,” Kavanaugh said.

He also avoided Democratic Senator Patrick Leahy’s question about whether a president could pardon himself, or someone else, in exchange for a promise not to testify against him.

Slideshow ( 13 images )

Trump claimed in a Twitter post in June “the absolute right to PARDON myself.”

Kavanaugh said: “The question of self-pardons is something I have never analyzed.”

In citing examples of judicial independence, Kavanaugh lauded a 1974 ruling that ordered President Richard Nixon to hand over subpoenaed materials during the Watergate scandal and a 1954 Supreme Court ruling that ended racial segregation in public schools.

Feinstein asked Kavanaugh about his 2009 article that concluded sitting presidents should be free from the distractions of civil lawsuits, criminal prosecutions and investigations. Kavanaugh promised a “completely open mind” if such issues came before him as a Supreme Court justice.

Slideshow ( 13 images )

‘GRASPING AT STRAWS’

Trump told reporters at the White House he was pleased with the hearing and said: “The other side is grasping at straws.”

Liberals are concerned Kavanaugh could provide a decisive fifth vote on the nine-justice court to overturn the 1973 abortion ruling.

Kavanaugh called the Roe v. Wade decision “an important precedent of the Supreme Court that has been reaffirmed many times.” He highlighted the 1992 Planned Parenthood v. Casey ruling that reaffirmed Roe, calling it a “precedent on precedent.”

While stopping short of saying the Roe case correctly decided, Kavanaugh’s remarks suggested he might be cautious toward overturning it. But that may not preclude him from joining the court’s other conservatives in restricting its scope by upholding abortion restrictions enacted in conservative states.

Pressed by Democratic Senator Dick Durbin, Kavanaugh defended a ruling he took part in that issued an order preventing a 17-year-old illegal immigrant, detained by U.S. authorities in Texas, from immediately having an abortion. The ruling was later overturned and she had the abortion.

On gun rights, Feinstein pressed Kavanaugh on his 2011 dissent in an appellate ruling upholding a District of Columbia gun law banning semi-automatic rifles. Kavanaugh said then that such guns were covered by the U.S. Constitution’s Second Amendment, which protects the right to bear arms.

“Of course the violence in the schools is something we all detest and want to do something about,” Kavanaugh said.

Responding to questions from Democratic Senator Cory Booker on race issues, including promoting diversity in education, Kavanaugh cited cases in which he ruled in favor of minorities and his efforts to hire law clerks from diverse backgrounds

“I have done my best to understand the real world and apply the law fairly.” Kavanaugh said.

Trump picked Kavanaugh, 53, to replace Justice Anthony Kennedy, who announced his retirement in June.