WASHINGTON (REUTERS) - Mr Brett Kavanaugh, President Donald Trump's Supreme Court nominee, embraced the importance of judicial independence on Wednesday (Sept 5) during his US Senate confirmation hearing, but sidestepped questions from Democrats about whether a president possesses the power to pardon himself or must respond to a court subpoena.

On the second day of the contentious hearing, senators pressed the conservative federal appeals court judge on his views on presidential power, abortion and gun rights.

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

He condemned the spate of US school shootings, but defended an opinion he wrote questioning whether semi-automatic rifles could be banned.

Mr Trump has often criticised the federal judiciary, and some liberals fear Mr Kavanaugh could serve as a rubber stamp for the President.

Asked by the Judiciary Committee's Republican chairman, Mr Chuck Grassley, whether he would have any trouble ruling against Mr Trump or the executive branch, Mr 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," he added.

Mr Kavanaugh cited his opinion in a case involving a Guantanamo Bay detainee that went against Republican former president George W. Bush, who appointed him to his current judgeship.

But Mr 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 Mr Trump's 2016 presidential campaign and Russia.

"I can't give you an answer on that hypothetical question," Mr Kavanaugh said, noting that previous high court nominees also avoided queries about matters that might later come before them.

Kavanaugh similarly dodged Democratic Senator Patrick Leahy's question about whether a president has the power to issue a pardon to himself or to someone else in exchange for promising not to testify against him.

Mr Trump, in a June Twitter post, claimed "the absolute right to PARDON myself".

In citing examples of judicial independence, Mr Kavanaugh mentioned a 1974 ruling ordering then President Richard Nixon to hand over subpoenaed materials during the Watergate scandal, and a 1954 Supreme Court ruling ending racial segregation in public schools.

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

If confirmed, Mr 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 Mr 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 Mr Kavanaugh will be confirmed to the lifetime job on top US judicial body.

As they did the day before, a succession of shouting protesters interrupted the session, opposing Mr Kavanaugh's nomination, before being removed by security personnel.

Mr Trump told reporters at the White House that he was pleased with the hearing, and said "the other side is grasping at straws".

Sitting alone at a table facing a bank of senators, Mr Kavanaugh stressed the difficulty of deciding tough legal disputes and noted "real-world consequences" of his rulings.

ABORTION RIGHTS

Regarding abortion, he said he does not "live in a bubble" and understood people's strong feelings.

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

Mr Kavanaugh called the Roe decision "an important precedent of the Supreme Court that has been reaffirmed many times".

He highlighted the 1992 Planned Parenthood versus Casey ruling that reaffirmed Roe, calling it a "precedent on precedent".

While stopping short of calling the Roe case correctly decided, Mr Kavanaugh's remarks suggested he might be cautious towards 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, Mr Kavanaugh defended a ruling he took part in issuing an order preventing a 17-year-old illegal immigrant detained by US authorities in Texas from immediately having an abortion. The ruling was later overturned and she underwent the abortion.

On gun rights, Ms Feinstein pressed Mr Kavanaugh on his 2011 dissent in an appellate ruling upholding a District of Columbia gun law banning semi-automatic rifles. Mr Kavanaugh said such guns are covered by the US Constitution's Second Amendment, which protects the right to bear arms.

Mr Kavanaugh said his opinion 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," Mr Kavanaugh said.

But handguns and other semi-automatic weapons are also used for hunting and self defence, he added.

The Supreme Court to date has ruled that individuals have a right to bear arms in self defence, but has not extended that right outside the home or specified which weapons are covered.

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