WASHINGTON, D.C. — On Thursday, U.S. Supreme Court nominee Brett Kavanaugh stressed that he believes the judiciary has broad authority to check the power of the White House, but refused to criticize the man who selected him, President Trump.

In a second day of testimony, Kavanaugh declined to comment on Trump’s criticism of the judiciary or offer praise of the president’s character.

Democrats at Kavanaugh’s Senate confirmation hearing also pressed the conservative federal appeals court judge over newly released emails highlighting his views on abortion and racial issues after a partisan fight over the public release of the documents.

The documents released on Thursday dated from Kavanaugh’s service in the White House under Republican President George W. Bush more than a decade ago. Democrats had objected to an earlier decision by the Senate Judiciary Committee’s Republican leadership not to make the emails public.

The third day of the confirmation hearing again was repeatedly interrupted by protesters hostile to Kavanaugh. The nominee, enduring back-to-back days of lengthy questioning, remained in good humor, making no gaffes that were likely to derail his confirmation in a Senate narrowly controlled by Trump’s fellow Republicans, despite the efforts of Democrats opposed to him.

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

Asked by Democratic Senator Cory Booker whether he was picked because of an expectation of loyalty to Trump, Kavanaugh responded, “My only loyalty is to the Constitution. I’m an independent judge.”

Kavanaugh refused to say whether he had “the greatest respect” for Trump, a phrase Booker said he had used when describing Bush.

Democratic Senator Dick Durbin said Kavanaugh’s nomination comes at a time when Trump poses a threat to America’s rule of law and is facing an ongoing special counsel investigation. Kavanaugh said his 12 years as a judge demonstrated he was unafraid “to invalidate executive power when it violates the law.”

Kavanaugh had declined on Wednesday to answer whether a president would have to respond to a court’s subpoena, saying he could be asked to rule on the matter. But under questioning by Durbin on the scope of presidential power, Kavanaugh underscored judicial authority.

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