Washington CNN  — 

Missouri Democratic Sen. Claire McCaskill said Wednesday she is voting no on Judge Brett Kavanaugh’s nomination to the Supreme Court, citing concerns over his stance on anonymous political contributions.

McCaskill’s position is significant given that she is running for re-election this year in a state President Donald Trump won in 2016, and Kavanaugh’s supporters are targeting Democrats in red or purple states as possible “yes” votes. Republicans, however, hold a 51-49 majority in the chamber and could still confirm Kavanaugh’s appointment even if all Democrats were to oppose his nomination.

McCaskill said in a statement her decision is not based on the allegations of sexual assault in the 1980s against the judge made by California professor Christine Blasey Ford, “but rather on his positions on several key issues, most importantly the avalanche of dark, anonymous money that is crushing our democracy.” Kavanaugh has denied Ford’s allegations.

“He has revealed his bias against limits on campaign donations which places him completely out of the mainstream of this nation,” McCaskill said. “Judge Kavanaugh will give free reign to anonymous donors and foreign governments through their citizens to spend money to interfere and influence our elections with so-called ‘issue ads.’”

The senator said the “issue ads” are flooding airwaves “to directly influence election outcomes, drowning the concept of individuals having the strongest voice in our democracy,” and expressed concern that Kavanaugh has said there should be no restrictions on the ads.

McCaskill said she is also uncomfortable about Kavanaugh’s view on “presidential power as it relates to the rule of law, and his position that corporations are people,” but said “it is his allegiance to the position that unlimited donations and dark anonymous money, from even foreign interests, should be allowed to swamp the voices of individuals that has been the determining factor in my decision to vote no on his nomination.”

CNN’s Phil Mattingly contributed to this report.