Even without considering allegations of sexual assault, Brett Kavanaugh should not be confirmed for the Supreme Court.
Nominations to the U.S. Supreme Court are made on the basis of political beliefs. President Trump has said that he would nominate people who would overturn Roe v. Wade. https://www.npr.org/2018/07/03/625410441/which-trump-should-be-believed-on-overturning-roe-v-wade. Trump has said that he will nominate justices from the recommendations of the conservative Federalist Society. https://www.reuters.com/article/us-usa-trump-court/trump-adds-five-conservatives-to-list-of-possible-supreme-court-picks-idUSKBN1DH2Q2.
Members of the U.S. Senate fulfilling their duty to advice and consent in the case of the nomination of Brett Kavanaugh should vote on partisan, that is, policy grounds.
An argument can be made that the president was elected by the people (Electoral College) and should be able to put his own people in place (assuming that the individuals are not disqualified for non-political reasons) for administrative positions to carry out the political philosophy that voters supported in the presidential election. But the voters have also supported the political philosophies of the 100 members of the U.S. Senate and the 435 members of the House of Representatives. It should be noted that in 2016 almost three million more voters supported Clinton than Trump.
The U.S. Supreme Court is one of three, independent branches of the U.S. government as set out in the U.S. Constitution. Although holding personal political views, the justices must decide cases, taking into account established law, based on whether legislation or executive action is consistent with the Constitution and must protect the rights of individuals. Kavanaugh's record suggests that he will depart from important precedents and that he will not provide the appropriate check to the executive branch of government.
1. Kavanaugh supports an unchecked presidency.
(a) Review his obsequious statement (also known as an unnecessary lie) at the press conference announcing his appointment where he said of President Trump: “No president has ever consulted more widely or talked with more people from more backgrounds to seek input about a supreme court nomination.” https://www.vox.com/2018/7/9/17550910/brett-kavanaugh-nomination-transcript-supreme-court
(b) “He believes the president is above the law. In his personal writing, Judge Kavanaugh has repeatedly demonstrated that he won’t stand up to President Donald Trump, allowing President Trump’s abuses of power to go unchecked. He has argued that a president should have ‘absolute discretion’ and be able to dismiss any counsel 'out to get him,' that a president need not comply with laws that he personally deems to be unconstitutional, and that a president is protected from ‘criminal prosecution and investigation’ while he or she is in office. [Footnotes omitted.]” http://www.nationalpartnership.org/research-library/general/seven-reasons-confirming-brett-kavanaugh-would-be-terrible-for-women.pdf
(c) “Judge Kavanaugh openly criticized Chief Justice Roberts for his decision to uphold the health care law and, from the bench, repeatedly voiced his opposition to the ACA, including by suggesting that a president could ‘decline to enforce’ this lifesaving legislation if he [the president] personally deems it unconstitutional. [Footnotes omitted.]” http://www.nationalpartnership.org/research-library/general/seven-reasons-confirming-brett-kavanaugh-would-be-terrible-for-women.pdf
2. Kavanaugh will likely vote to weaken or overturn Roe v. Wade, family planning laws, LGBT rights, and privacy laws.
U.S. Senator Maggie Hassan has written: “Judge Kavanaugh challenged whether it was accurate to say that Roe v. Wade is the 'settled law of the land.' Writing in an email, 'I am not sure that all legal scholars refer to Roe as the settled law of the land at the Supreme Court level since Court can always overrule precedent, and three current Justices on the Court would do so.' As recently as last year, Judge Kavanaugh praised the dissent from Justice Rehnquist in Roe v. Wade . . . .” https://www.hassan.senate.gov/news/press-releases/senator-hassan-announces-opposition-to-judge-kavanaugh-for-the-supreme-court
3. A candidate who is found to have lied should be denied an appointment.
Kavanaugh was evasive and may have lied to the U.S. Senate in his confirmation hearing to be a U.S. Circuit Court Judge. https://www.motherjones.com/politics/2018/09/five-times-brett-kavanaugh-appears-to-have-lied-to-congress-while-under-oath/
After hearing(s) and/or further investigation, Senators may conclude that Kavanaugh was evasive and may have lied regarding sexual assault charges.