Brett Kavanaugh’s substantial record as a federal appeals court judge over the past 12 years has taken a back seat to other issues since President Donald Trump nominated him on July 9. Here are the five major controversies:

Most important seat

This isn’t just any Supreme Court seat. It’s Anthony Kennedy’s. The retired justice represented the swing vote on key questions, often siding with the court’s four liberal justices. In the past three years alone, that included abortion rights, affirmative action and same-sex marriage.

“The rhetoric is now overheated because we are talking about replacing Justice Kennedy,” says John Malcolm, vice president at the conservative Heritage Foundation, which helped assemble Trump’s list of 25 potential nominees. “From the Democrats’ perspective, this matters more.”

Partisan Background

Kavanaugh’s years investigating President Bill Clinton as part of independent counsel Ken Starr’s team and working in the White House for President George W. Bush represent an unusually partisan background for a judge. But, despite the release of hundreds of thousands of pages of records, much of it remains under wraps.

“We have lawyers going over these documents day and night and weekends. They are so redacted,” says Nan Aron, president of the liberal Alliance for Justice. She says Republicans have tried to “hide any information that might be damaging.”

Missing documents

As a deputy White House counsel and Bush’s staff secretary from 2001 to 2006, Kavanaugh was involved in myriad policy decisions and political disputes. That translates into the biggest paper trail for any high court nominee, but most of it has not been released because Senate Republicans claim it’s irrelevant.

“We go into this hearing with a cloud over the proceedings because of the way that the Republican majority in the Senate has thumbed its nose at an attempt to get a complete record,” says Elizabeth Wydra, president of the liberal Constitutional Accountability Center.

Ongoing investigations

Unlike Neil Gorsuch, Trump’s first nominee who was confirmed in April 2017, Kavanaugh has emerged amid criminal inquiries into Russian interference and campaign finance violations during the 2016 election. That increases the likelihood the high court may stand in judgment of the president – and Kavanaugh has said presidents shouldn’t be questioned while in office.

“The translation of this is, Trump is picking his juror,” says Neera Tanden, president of the liberal Center for American Progress.

Upcoming elections

The midterm elections on Nov. 6 offer Democrats a slim chance of winning a Senate majority, in which case they could defeat Kavanaugh’s nomination and any other Trump nominee. Republicans will have a 51-49 majority going into the confirmation vote once Sen. John McCain’s replacement is named.

“The thing that makes this the most challenging is the thin margin in the Senate,” says Carrie Severino, policy director at the conservative Judicial Crisis Network.