WASHINGTON, Sept 5 (Reuters) - Brett Kavanaugh, President Donald Trump's U.S. Supreme Court nominee, on Wednesday underscored the importance of judicial independence and called a 1973 ruling legalizing abortion an important legal precedent that has been reaffirmed over the years in the second day of his Senate confirmation hearing.
"I think the first quality of a good judge in our constitutional system is independence," the conservative federal appeals court judge said in response to a question by the Judiciary Committee's Republican chairman, Chuck Grassley.
"No one is above the law in our constitutional system," added Kavanaugh, who was facing his first questions from senators after giving an opening statement on Tuesday.
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Kavanaugh indicated he was willing to issue rulings against a president who appointed him, noting his ruling in a case involving a Guantanamo Bay detainee that went against Republican former President George W. Bush, who appointed him to his current judicial job.
But Kavanaugh sidestepped a question by Democratic Senator Dianne Feinstein 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, noting that previous high court nominees also have declined to answer queries about cases that might later come before them.
As they did the day before, protesters repeatedly interrupted the session, opposing Kavanaugh's nomination, before being removed from the room by security personnel.
The confirmation hearing opened on Tuesday with a chaotic session in which Democrats complained that Republicans withheld documents concerning Kavanaugh's work in Bush's White House more than a decade ago that they said they needed to review to properly vet the nominee. Capitol Police on Tuesday removed 61 protesters opposed to Kavanaugh from the room and charged them with disorderly conduct.
Trump has often criticized the federal judiciary. Kavanaugh underscored the importance of judicial independence, saying, "That takes some backbone. That takes some judicial fortitude."
In citing examples of judicial independence, Kavanaugh mentioned a 1954 ruling ending racial segregation in public schools and a 1974 ruling ordering President Richard Nixon to hand over subpoenaed materials during the Watergate scandal.
He said he would respect past Supreme Court rulings.
If confirmed, Kavanaugh is expected to move the court, which already had a conservative majority, further to the right. Senate Democrats have vowed a fierce fight. But with Trump's fellow Republicans holding a slim majority in the Senate, and with no sign of any of them voting against the nomination, it remains likely Kavanaugh will be confirmed to the lifetime job on top U.S. judicial body.
Democrats started to question Kavanaugh on abortion and gun rights, among other issues.
Kavanaugh said that the 1973 Roe v. Wade decision that legalized abortion nationwide is "an important precedent of the Supreme Court that has been reaffirmed many times." He specifically mentioned a 1992 ruling in the case Planned Parenthood v. Casey reaffirming the Roe ruling.
Liberals are concerned Kavanaugh could provide a decisive fifth vote on the nine-justice court to overturn the 1973 ruling.
On gun rights, Feinstein pressed Kavanaugh on a 2011 case in which he dissented as the appeals court on which he sits upheld a District of Columbia gun law that banned semi-automatic rifles. Kavanaugh said such guns are covered by the U.S. Constitution’s Second Amendment, which protects the right to bear arms.
Kavanaugh defended his opinion, saying it was based on Supreme Court precedent that indicated semi-automatic weapons are in common use.
"Of course the violence in the schools is something we all detest and want to do something about," Kavanaugh said.
But handguns and other semi-automatic weapons are also used for hunting and self-defense, he added.
The Supreme Court to date has ruled that individuals have a right to bear arms in self defense but has not extended that right outside the home or specified which weapons are covered.
Feinstein also asked Kavanaugh about a 2009 article he wrote in which he concluded that presidents should be free from the distractions of civil lawsuits, criminal prosecutions and investigations while in office.
Kavanaugh said he would have a "completely open mind" if the legal issues came before him as a judge.
"They were ideas of Congress to consider, they were not my constitutional views," he said of the article.
Trump picked Kavanaugh to replace Justice Anthony Kennedy, who announced his retirement on June 27. At age 53, Kavanaugh could serve on the court for decades.
(Reporting by Lawrence Hurley, Ginger Gibson and Amanda Becker; Editing by Will Dunham)