Washington (CNN) Brett Kavanaugh emerged from two days of tough questioning in the Senate Judiciary Committee without making any obvious missteps that could imperil his confirmation as the justice who will pull the Supreme Court to the right and hand Donald Trump a generational presidential legacy.

He avoided ceding ground on the most contentious issues, either by saying he wanted to keep "three zip codes" away from politics or by arguing that he could not comment on "hypothetical" cases that could come before him on the nation's top bench.

Kavanaugh refused to say whether a sitting president must respond to a subpoena -- not an academic issue in the age of Trump. He declined to agree to Democratic calls for him to recuse himself from any cases related to the Russia investigation. And he would not say where he would come down on abortion, amid expectations among conservatives he would like to overturn Roe v. Wade.

But Democrats did not walk away from a deeply divisive hearing with nothing. Top lawmakers showed vigor in cross examining Kavanaugh and by portraying him as Trump's man on the court and may have at least partly lived up to expectations of the party's fired up base for a show of backbone ahead of the mid-term elections.

After emerging largely unscathed after the final round of questions from senators that stretched late into Thursday evening, Kavanaugh could take comfort in passing his biggest test. If Republicans stick together he is almost certain to be confirmed while minority Democrats face their own challenge in keeping the votes of red state senators with tough re-election races in their column.

Booker's document fight

Thursday's hearing featured another bitter showdown between Democrats who are furious at the failure of the White House to hand over tens of thousands of key documents on time or at all, and at restrictions on the public release of material that was made available.

New Jersey Democrat Cory Booker said he was ready to risk expulsion from the Senate for making public documents pertinent Kavanaugh's time as a top White House aide to President George W. Bush, but the GOP mocked him for grandstanding ahead of a possible 2020 run -- saying it had already cleared the emails for release.

In a striking political gambit, Booker, backed up by Democratic Sen. Mazie Hirono of Hawaii, released emails -- which had been designated as "committee confidential" -- that reference Kavanaugh's position on racial profiling and thoughts on Roe v. Wade dating from his time as a White House official under Bush.

Booker, who as a potential 2020 presidential candidate had an incentive to make a splash in the hearing, said he took the action as an act of "civil disobedience."

"I understand the penalty comes with potential ousting from the Senate. ... I openly invite and accept the consequences of my team releasing that email right now," Booker said.

"This is about the closest I'll probably ever have in my life to an 'I am Spartacus' moment," he added.

Republican Sen John Cornyn warned Booker that releasing documents marked "committee confidential" would break Senate rules.

"Running for president is not an excuse for violating the rules of the Senate," the Texas Republican said.

Later Thursday, Bill Burck, a lawyer who oversaw the process of providing Bush administration documents, undercut Booker's grand gesture, saying that the material in question had been cleared on Wednesday night at the request of the senator's staff.

"We were surprised to learn about Senator Booker's histrionics this morning because we had already told him he could use the documents publicly. In fact, we have said yes to every request made by the Senate Democrats to make documents public," Burck said in a statement.

The office of Judiciary Chairman Chuck Grassley, an Iowa Republican, also said that senators, including Booker, were notified "before they spoke today" that the restrictions on the documents had been waived.

Booker, however, insisted he was in the right, saying he read from the documents aloud in the hearing on Wednesday night long before they were cleared at around 4 a.m. Democrats have repeatedly complained that the White House is withholding tens of thousands of documents relevant to the nomination and wants many more that have been provided released to the public.

The New Jersey senator also said he doubted Cornyn would follow through on his threats to enforce Senate discipline against him.

"I think he's like a lot of bullies are: a lot of talk, no action," Booker said.

North Carolina Republican Sen. Thom Tillis took exception to his Democratic colleague's tactics.

"Certainly in the six hours between the time that email hit your email box and the theatrics that happened in this chamber today you could have actually found out that you didn't have to be Spartacus, you didn't have to go interact with civil disobedience, you got what you wanted," Tillis said.

The schoolyard taunts underlined how the hearing, ahead of what appears to be Kavanaugh's likely confirmation, has become another battlefield in the vicious partisanship and complete lack of trust between the parties that is wracking Washington at a critical moment of the Trump era

Booker's intervention followed a set of glowing reviews from liberals for another potential 2020 Democratic presidential candidate on the Judiciary Committee, Sen. Kamala Harris of California, who late Wednesday night appeared to discomfort Kavanaugh with a series of questions designed to find out with whom he had discussed special counsel Robert Mueller's Russia investigation.

Harris returned to the question on Thursday evening, saying that she had been working on "reliable information" that Kavanaugh had a conversation about the probe with someone from Kasowitz Benson Torres, the law firm founded by Trump's personal attorney Marc Kasowitz.

Kavanaugh had sidestepped the question on Wednesday, so Harris asked him again and he replied "the answer's no."

Earlier, the firm said in a statement to CNN there had been no such discussions.

Harris did not disclose the "reliable information" on which she based her questions.

JUST WATCHED Senator challenges Kavanaugh on Mueller probe Replay More Videos ... MUST WATCH Senator challenges Kavanaugh on Mueller probe 02:55

2003 email shows Kavanaugh discussing Roe

In another flashpoint development, a previously unreleased 2003 email from Kavanaugh, while he was an official in the Bush White House, shows him raising the point of whether Roe v. Wade, the 1973 Supreme Court ruling that upheld the right to an abortion, was settled law of the land.

In the internal White House email, obtained by CNN, Kavanaugh wrote: "I am not sure that all legal scholars refer to Roe v. Wade as the settled law of the land at the Supreme Court level since Court can always overrule its precedent, and three current Justices on the Court would do so."

"The point there is in the inferior court point," Kavanaugh wrote, responding to a draft op-ed that had been circulated for edits between lawmakers and White House staff.

The draft, meant to be submitted under the name of "high-profile, pro-choice" women in support of a Bush judicial nominee, had said that "it is widely understood accepted by legal scholars across the board that Roe v. Wade and its progeny are the settled law of the land."

During the confirmation hearing on Wednesday, Kavanaugh said: "As a general proposition I understand the importance of the precedent set forth in Roe v. Wade."

Trump said during his campaign that he would appoint Supreme Court justices who would overturn Roe. In recent years, Supreme Court nominees have gotten through their confirmation hearings by refusing to say how they would rule on what they say is a hypothetical future case on the issue.

The New York Times first reported the email.

Throughout the contentious hearing, now in its third day, Kavanaugh has tried to give political questions -- especially those related to Trump and his potential legal woes -- a wide berth.

On Wednesday he insisted that "no one is above the law" but declined to say whether a sitting president must respond to a subpoena.

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.

Booker warned that given Trump's frequent attacks on the Justice Department there was a "shadow over the independence of the judiciary" and said it was understandable for some Americans to wonder whether a nominee picked by the President would owe loyalty to him or had been nominated to shield him from a criminal investigation.

"My only loyalty is to the Constitution," Kavanaugh responded. "I have made that clear, I am an independent judge."