Heitkamp said she was concerned about Kavanaugh's temperament after his emotional performance before the Senate Judiciary Committee.
It also suggests the tumultuous battle over his nomination could harm the court's reputation as the nonpartisan branch of government.
Protesters demonstrate on first day with newly sworn in Associate Justice Brett Kavanaugh on the court at the Supreme Court in Washington, U.S., October 9, 2018. Roughly a third said it would make no difference in their vote (22 percent) or had no opinion (10 percent). Women say the episode draws them toward Democrats over Republicans by a 16-point margin, while men are more evenly split.
"Through his presiding role in the court's conferences and his assignment of court opinions, he might redouble his efforts to find compromises that avoid party-line votes in cases", they wrote.
The outlook in Texas and Tennessee is more bleak for Democrats.
Rep. Jerrold Nadler, D-N.Y., has promised an investigation into sexual misconduct and perjury allegations against Kavanaugh, which he vehemently denies, if the Democrats take control of the House in the midterm elections. Democrats at his confirmation hearing further accused Kavanaugh of dishonesty over his answers to questions regarding his work in the George W. Bush White House. "The other side did it", he told reporters after the swearing-in ceremony at the White House.
Kavanaugh's wife watched the lively session as did his daughters, who were granted a day off from school to see their father's first day on the nation's top court.
Since justices serve lifetime appointments, the political consequences are likely to last long beyond Trump's administration.
The president - whose Republicans fear losing at least the lower chamber of Congress in November - angrily predicted that the Kavanaugh row would backfire on Democrats.
Across all 13 states, 40 percent of the midterm voters are likely to be "base Republicans", regular midterm voters who essentially never split their ticket. "In this week's poll, 70 percent of voters say they are very motivated to vote - including 77 percent of Democrats, 68 percent of Republicans, and 60 percent of independents".
But the electoral landscape has since changed significantly in the Republicans' favor.
Clearing the judicial nominees provided a signature walk-off for Senate Majority Leader Mitch McConnell, R-Ky., who has focused on reshaping the judiciary with more conservative jurists. That nets to 61 percent support among 18- to 49-year-olds, dropping to 49 percent of Americans age 50-64 and 38 percent of seniors.
Women not only tilt against Kavanaugh, but do so with more gusto.
Though some Democrats would oppose the amendment because ideally they would like to pack the Court, I wonder how many Democrats trust the Republicans in the future to be less partisan than they would be.
The political opposition in the United States led by the Democratic Party hopes to win enough votes in the elections to win control of the Senate which, with its key role in an impeachment process, would have a restraining effect on some of President Trump's disputed decisions.
Gatherings like these should take place in October in other States, including some traditionally sympathetic to republicans, such as Texas, Georgia or SC.