Washington (CNN) Brett Kavanaugh spent much of 12 hours in a packed and raucous Senate hearing room Wednesday trying not to talk about politics -- or how he would act in cases involving the man who nominated him to the Supreme Court, President Donald Trump.

Should the Senate confirm Kavanaugh, it would likely ensure a conservative majority for a generation and bolster Trump's legacy in reshaping the judiciary. But special counsel Robert Mueller's ongoing investigation into Russian interference in the 2016 election and other legal controversies surrounding the White House mean a Trump-specific case could hit the Supreme Court sooner rather than later.

"No one is above the law in our constitutional system," Kavanaugh said, adding that the presidency is not a monarchy.

But he refused to be drawn by Democrats into treacherous political areas. He declined to say if a sitting president must respond to a subpoena, and would not budge when asked whether a president could pardon himself.

"The question of self pardons is something I have never analyzed, it is a question I have not written about, it's a question therefore that is a hypothetical question that I cannot begin to answer in this context as a sitting judge and as a nominee to Supreme Court," Kavanaugh said.

Trump earlier this year claimed he had an "absolute" right to pardon himself should he choose to.

Senate Democrats have suggested that Kavanaugh could be biased in favor of the President and worry that his views on the primacy of executive power could help Trump evade legal scrutiny.

When asked whether a sitting President should be forced to respond to a subpoena, Kavanaugh said, "My understanding is that you're asking me to give my view on a potential hypothetical, and that is something that each of the eight justices currently sitting on the Supreme Court, when they were sitting in my seat, declined to decide potential hypothetical cases."

On whether he would recuse himself if an issue involving the President's criminal or civil liability came before the Supreme Court, Kavanaugh said: "I should not and may not make a commitment."

Kavanaugh also avoided a chance to discuss "political controversy" when GOP Sen. Jeff Flake asked about Trump's recent tweet on the Justice Department prosecuting two Republican congressmen -- both early Trump allies.

"I don't think we want judges commenting on the latest political controversy, because that would ultimately lead the people to doubt whether we're independent or whether we're politicians in robes, and so maintaining that strict independence of the judiciary requires me, I think, to avoid commenting on any current events," Kavanaugh said.

He repeated that sentiment just before 10 p.m. Wednesday night, when Democratic Sen. Kamala Harris asked about Trump's claim that "both sides" were to blame for the violence in Charlottesville last year.

"I am not here to assess comments made in the political arena, because the risk is I'll be drawn into the political arena," Kavanaugh said.

Abortion and gun control

Over and over Wednesday, Kavanaugh, who was calm and disciplined during a long day of scrutiny from Democrats under pressure from grassroots activists to show vigorous resistance to Trump's nominee, argued that judges must be independent and must confine their rulings to precedent.

On abortion, Kavanaugh said that he viewed the 1973 Roe v. Wade decision upholding a woman's right to an abortion as settled precedent of the Supreme Court under the doctrine of stare decisis.

Roe v. Wade is "entitled to respect" he said, adding that he understands the passion around the decision.

"I don't live in a bubble. I understand. I live in the real world. I understand the importance of the issue," he said.

But Democratic Sen. Dianne Feinstein raised doubts that a nominee's position would hold when it comes to ruling on abortion from the bench.

"When the subject comes up, the person says we will follow stare decisis, and then they get confirmed and they don't," she said of previous nominees.

Feinstein also chose to drill down on gun control and school shootings, asking Kavanaugh to explain his dissent in a 2011 DC Circuit case upholding the District of Columbia's ban on the possession of most semi-automatic rifles.

Kavanaugh argued that his reasoning was based on the Supreme Court's majority decision in the Heller case, a 2008 ruling authored by Justice Antonin Scalia, that held that semi-automatic rifles were constitutionally protected.

While decrying gun violence and sympathizing with Feinstein's horror over school shootings, Kavanaugh said, "I understand the issue, but as a judge, my job was to follow the Second Amendment opinion of the Supreme Court whether I agree with it or disagree with it."

Wednesday's testimony was frequently interrupted by protestors who were led screaming out of the hearing room. But the proceedings lacked the bitterness and partisan sniping that characterized the opening day of the hearing on Tuesday.

Democrats are under pressure to show their voters that they have the backbone to challenge the administration and also want to make clear to their voters the huge stakes of getting out to vote -- since the GOP victory in 2016 gave Trump the chance to significantly tug the Supreme Court to the right, possibly for decades.

The President himself said that he was pleased with Kavanaugh's performance so far, saying he was "born for the position."

"I watched today for a little while. I saw some incredible answers to some very complex questions," Trump told reporters.

Has support from Manchin, GOP senators

In order to stop Kavanaugh from being confirmed, Democrats must keep their entire coalition together in the Senate and hope to pick off two Republicans, with the most likely options being Alaska Sen. Lisa Murkowski and Susan Collins of Maine.

But there is also the chance that some Democrats, facing tough re-election races in states that Trump won handsomely in 2016, will be forced by their own hopes of political survival to vote for Kavanaugh.

One potential Democratic defector, Sen. Joe Manchin of West Virginia, told CNN that he has so far seen nothing disqualifying in the nominee's testimony.

"He's handled himself very professionally. ... His dialogue is more specific in his approach to being a jurist," Manchin said, adding that he felt the behavior of Republican and Democratic senators in the hearing had been deplorable. "That's what makes people sick," he said.

Republicans, meanwhile, remain confident. Kavanaugh has not only testified twice before, he worked on judicial nominations while serving in the George W. Bush White House. He understands the process better than most. He's been participating in "murder boards" -- practice sessions -- with clerks and Justice Department lawyers taking on the roles of senators, according to a participant.

The hearing will resume at 9:30 a.m. Thursday with another round of questions from senators.