WASHINGTON - The Senate confirmation hearing for Brett Kavanaugh, President Donald Trump's US Supreme Court pick, descended into chaos on Tuesday, as Democrats protested about Republicans blocking access to documents concerning the nominee's White House work more than a decade ago.With Democratic senators repeatedly interrupting the Judiciary Committee's Republican chairman Chuck Grassley at the outset of the hearing and dozens of shouting protesters removed one by one by security personnel, the session quickly became a ruckus. Some seven hours after the hearing began, Kavanaugh - the conservative federal appeals court judge picked by Trump for a lifetime job on the top US judicial body - finally made his opening remarks.Kavanaugh, nominated by a president who has sharply criticized the federal judiciary, told the senators that "a judge must be independent, not swayed by public pressure. Our independent judiciary is the crown jewel of our constitutional republic."He called the Supreme Court "the last line of defense for the separation of powers (in the US government), and the rights and liberties guaranteed by the Constitution.""The Supreme Court must never be viewed as a partisan institution," Kavanaugh said."A judge must be independent and must interpret the law, not make the law," he added. "... A good judge must be an umpire - a neutral and impartial arbiter who favors no litigant or policy."The hearing got off to a rocky start, with Democrats decrying the withholding of the documents and asking to have the proceedings adjourned as Grassley struggled to maintain order."This is the first confirmation for a Supreme Court justice I've seen, basically, according to mob rule," Republican Senator John Cornyn said, a characterization Democrats rejected."What we've heard is the noise of democracy," Democratic Senator Dick Durbin said.Protesters, mostly women, took turns yelling as senators spoke, shouting, "This is a travesty of justice," "Our democracy is broken" and "Vote no on Kavanaugh." Demonstrators voiced concern about what they saw as the threat posed by Kavanaugh to abortion rights, healthcare access and gun control."We cannot possibly move forward. We have not had an opportunity to have a meaningful hearing," Democratic Senator Kamala Harris said. Democratic Senator Cory Booker appealed to Grassley's "sense of decency and integrity" and said the withholding of the documents by Republicans and the White House left lawmakers unable to properly vet Kavanaugh.Grassley called the Democrats' request to halt the hearing "out of order" and accused them of obstruction. Republicans hold a slim Senate majority and can confirm Kavanaugh if they stay united. There were no signs of Republican defections.If confirmed, Kavanaugh is expected to move the court - which already had a conservative majority - further to the right. Senate Democratic leaders have vowed a fierce fight to try to block his confirmation. Democrats signaled they would press Kavanaugh on abortion, gun rights and presidential power when they get to question him on Wednesday in a hearing due to run through Friday.Republican Orrin Hatch accused Democratic senators of political opportunism, noting, "We have folks who want to run for president," though he did not mention any by name. There has been speculation Booker and Harris might consider 2020 presidential runs.Hatch grew visibly irritated as protesters interrupted him."I think we ought to have this loudmouth removed," Hatch said.Trump nominated Kavanaugh, 53, to replace Justice Anthony Kennedy, who announced his retirement on June 27.Democrats have demanded in vain to see documents relating Kavanaugh's time as staff secretary to Republican former President George W. Bush from 2003 to 2006. That job involved managing paper flow from advisers to Bush. Republicans also have released some, but not all, documents concerning Kavanaugh's two prior years as a lawyer in Bush's White House Counsel's Office.Republicans have said Democrats have more than enough documents to assess Kavanaugh's record, including his 12 years of judicial opinions as a judge on the US Court of Appeals for the District of Columbia Circuit.STARING STRAIGHT AHEADKavanaugh sat, fingers intertwined, quietly staring ahead at the committee members as protesters in the audience screamed while being dragged out of the room. He occasionally jotted notes on paper.As the hearing paused for a lunch break, Fred Guttenberg, whose daughter who was killed in the Parkland, Florida high school mass shooting in February, tried to talk to Kavanaugh but the nominee turned away. Video of the encounter was shared widely on social media."I guess he did not want to deal with the reality of gun violence," Guttenberg said on Twitter after the encounter.White House spokesman Raj Shah said security intervened before Kavanaugh could shake Guttenberg's hand.There is a long history of heated fights over US Supreme Court nominations, with anger in both parties. But the Democratic frustrations that boiled over on Tuesday had been simmering for more than two years.Democrats have accused Senate Republican leaders of stealing a Supreme Court seat by refusing to consider Democratic former President Barack Obama's nominee to the high court Merrick Garland in 2016, allowing Trump to fill a Supreme Court vacancy instead.Republicans also last year reduced the margin for advancing Supreme Court nominations from 60 votes in the 100-seat Senate to a simple majority in order to force through the confirmation of Trump's first high court nominee Neil Gorsuch.Grassley sought to turn the attention to Kavanaugh's qualifications, calling him "one of the most qualified nominees - if not the most qualified nominee - I have seen."The Senate is likely to vote on confirmation by the end of September. The court begins its next term in October.The hearing gave Democrats a platform to make their case against Kavanaugh ahead of November's congressional elections in which they are seeking to seize control of Congress from Republicans.Liberals are concerned Kavanaugh could provide a decisive fifth vote on the nine-justice court to overturn or weaken the landmark 1973 Roe v. Wade ruling legalizing abortion nationwide.Kavanaugh is likely to be questioned about his views on investigating sitting presidents and Special Counsel Robert Mueller's investigation into Russian meddling in the 2016 U.S. presidential election and possible collusion between Moscow and Trump's campaign."I find it difficult to imagine that your views on this subject escaped the attention of President Trump, who seems increasingly fixated on his own ballooning legal jeopardy," Democratic Senator Patrick Leahy said.