Brett Kavanaugh’s nomination to serve on the Supreme Court is the most contentious issue in the Senate, prompting intense partisan debate and numerous claims about his views.

President Donald Trump nominated the federal appeals court judge July 8 to fill the seat of retiring Justice Anthony Kennedy.

Here are the facts on four of Democrats’ negative claims about Kavanaugh, 53, who currently sits on the U.S. Court of Appeals for the District of Columbia Circuit.

1. Nixon and the Watergate Tapes

Senate Minority Leader Charles Schumer, D-N.Y., accused Kavanaugh of believing that, as president, Richard Nixon should not have had to surrender secretly recorded tapes during the Watergate scandal.

In a tweet, Schumer referred to the 1974 Supreme Court case that forced Nixon to turn over the tapes.

The high court ruled 8-0 in 1974 that the president’s claim of executive privilege isn’t absolute and in this case wasn’t based on national security concerns.

Kavanaugh has in fact written articles supportive of the high court ruling.

However, during a 1998 panel discussion, he suggested the court might have erred, if the arguments of the lawyers defending President Bill Clinton’s claims of executive privilege during the independent counsel’s probe during the 1990s was to be considered.

Kavanaugh was one of the lawyers working for independent counsel Ken Starr’s team. He was involved in litigation to force the Clinton White House to provide information, challenging claims of executive privilege.

After his tenure with Starr in 1998, Kavanaugh wrote in the Georgetown Law Review that there is “no need to revisit” the Nixon case and that the 1974 ruling “reflects the proper balance of the president’s need for confidentiality and the government’s interest in obtaining all relevant evidence for criminal proceedings.”

Kavanaugh added that “courts have rightly rejected the executive’s attempt to conceal [relevant] information, and Congress should codify those results to prevent future presidents from trying the same gambit.”

However, at a panel the next year, Kavanaugh raised the question on a panel that included a former Clinton lawyer. He said the Clinton legal claims of executive privilege were similar to the Nixon arguments.

Kavanaugh noted that the Clinton lawyer hadn’t argued that the Nixon case was wrongly decided, then said: “But maybe Nixon was wrongly decided, heresy though it is to say.”

“I’m curious to know what people who are upset about the recent privilege rulings think about the Supreme Court’s ruling in Nixon,” Kavanaugh said. “Should United States v. Nixon be overruled on the ground that the case was a nonjusticiable intrabranch dispute? Maybe so.”

The Democratic argument that this means Kavanaugh sides with Nixon is “just another embarrassing stunt” by Kavanaugh foes, said Carrie Severino, chief counsel for the Judicial Crisis Network, a conservative group that monitors judicial nominations.

“This was a rhetorical question pointing out the other side’s argument,” Severino said of Kavanaugh’s asking about the Nixon ruling.

Subsequently, Kavanaugh argued that that isn’t his view.

In a 2014 speech at the Notre Dame Law Review Symposium, Kavanaugh called the Nixon case among the three “most significant cases in which the judiciary stood up to the president.”

At a 2015 speech at Catholic University Columbus School of Law, he asserted:

An umpire or referee has to keep control of the game, and be able to make tough calls against the star players or the home team. As a judge, you must, when appropriate, stand up to the political branches and say some action is unconstitutional or otherwise unlawful. Whether it was Marbury, or Youngstown, or Brown, or Nixon, some of the greatest moments in American judicial history have been when judges stood up to the other branches, were not cowed, and enforced the law. That takes backbone, or what some call judicial engagement. To be a good judge and a good umpire, you have to possess strong backbone.

2. Prosecuting a President

Critics also point to Kavanaugh’s writing in a 2012 Minnesota Law Review article: “Congress might consider a law exempting a president—while in office—from criminal prosecution and investigation, including from questioning by criminal prosecutors or defense counsel.”

However, the article doesn’t say that is existing law or indicate how Kavanaugh would rule on the bench. He wrote current legal interpretation “is beyond the scope of this inquiry.”

He also wrote that Congress should impeach a president who does something wrong, as it has the power to do under the Constitution.

The article reflected on Kavanaugh’s time on a team prosecuting a president and coming off his time serving in the White House counsel’s office during the George W. Bush administration:

This is not something I necessarily thought in the 1980s or 1990s. Like many Americans at that time, I believed that the president should be required to shoulder the same obligations that we all carry. But in retrospect, that seems a mistake.

Looking back to the late 1990s, for example, the nation certainly would have been better off if President Clinton could have focused on Osama bin Laden without being distracted by the Paula Jones sexual harassment case and its criminal investigation offshoots.

The Supreme Court ruled 9-0 that Clinton must face the Jones civil suit, in which Clinton lied under oath about his affair with White House intern Monica Lewinsky, which prompted the criminal probe. That probe led to Clinton’s impeachment in the House for perjury and obstruction of justice in 1998. The Senate acquitted him.

“The result the Supreme Court reached in Clinton v. Jones—that presidents are not constitutionally entitled to deferral of civil suits—may well have been entirely correct; that is beyond the scope of this inquiry,” Kavanaugh wrote. “But the court in Jones stated that Congress is free to provide a temporary deferral of civil suits while the president is in office.”

He continued:

Congress may be wise to do so, just as it has done for certain members of the military. Congress should consider doing the same, moreover, with respect to criminal investigations and prosecutions of the president. In particular, Congress might consider a law exempting a president—while in office—from criminal prosecution and investigation, including from questioning by criminal prosecutors or defense counsel. …

If the president does something dastardly, the impeachment process is available. No single prosecutor, judge, or jury should be able to accomplish what the Constitution assigns to the Congress.

Still, lacking a strong argument against his nomination to the Supreme Court, the opposition to Kavanaugh’s confirmation is likely to rally around the argument that he would protect Trump, building a narrative off the Nixon comment and the Minnesota Law Review article, predicts Curt Levey, president of the Committee for Justice, a conservative legal group.

“We haven’t heard many objections to Kavanaugh forcing them to focus on the resistance,” Levey told The Daily Signal, referring to the anti-Trump resistance. “Democrats need a narrative the mainstream media will hammer every day.”

“The type of news coverage that will resonate with the [Democrat] base is a narrative that Trump is some sort of criminal and Kavanaugh will protect him,” Levey said.

“It is the best bet to turn out the base, because only a Democratic majority can stop him,” he said, referring to the president.

3. That Dissent on Obamacare

Kavanaugh actually is taking heat from both sides on the issue of Obamacare. Some conservative Republicans argue that he hasn’t been strong enough in opposing the constitutionality of the health care law. Democrats contend he won’t allow for insurance coverage for pre-existing conditions.

Kavanaugh’s only Obamacare ruling was somewhat vague.

In the 2011 case before the D.C. Circuit, Seven-Sky v. Holder, Kavanaugh wrote a dissenting opinion asserting that federal courts shouldn’t hear constitutional challenges to Obamacare.

In this case, a group of taxpayers sued, arguing the law’s mandate requiring individuals to buy health insurance went beyond the authority of Congress. Two of the three judges on a D.C. Circuit panel rejected the argument.

Rather than rejecting it, Kavanaugh suggested a court shouldn’t be ruling on the matter, because the mandate wouldn’t take effect until 2014.

He contended the court shouldn’t rule on the case at all because an old law, the 1867 Anti-Injunction Act, prevents courts from ruling on tax laws before they take effect:

There is a natural and understandable inclination to decide these weighty and historic constitutional questions. But in my respectful judgment, deciding the constitutional issues in this case at this time would contravene an important and long-standing federal statute, the Anti-Injunction Act, which carefully limits the jurisdiction of federal courts over tax-related matters.

It was among the early descriptions of the individual mandate as a tax—which became the rationale for the Supreme Court to uphold the mandate, and thus Obamacare, in a 2012 ruling.

Kavanaugh also wrote: “I do not take a position here on whether the statute as currently written is justifiable under the [Constitution’s] Taxing Clause or the Commerce Clause.”

However, his dissent did not favor Obamacare nor take a stance, but rather argued for judicial restraint.

A liberal group called Demand Justice has sponsored a commercial using the same case to claim that “Kavanaugh refused to uphold key patient protections in the past, and if he joins the court he could vote to end these protections for good.”

However, Kavanaugh’s dissent had little to say about the merits of whether Congress had the authority to include patient protections in the Obamacare law—such as requiring coverage for pre-existing condition. He neither agreed with nor rejected the protections in the law.

“The claim by the left on pre-existing is a general claim that if he found a way to get rid of Obamacare, there would be no more coverage of pre-existing conditions,” Thomas Jipping, a senior legal fellow at The Heritage Foundation, told The Daily Signal. “The problem with that theory is nothing is stopping Congress on the next day from passing pre-existing condition coverage.”

Some conservative pundits expressed concern that Kavanaugh was weak on the constitutionality of the Affordable Care Act, popularly known as Obamacare.

But, criticizing Kavanaugh for an individual case because one doesn’t like the ruling is not a way to evaluate a judge—rather it should be based on how a judge reaches a decision, Jipping said. He added that Kavanaugh seemed to be expressing judicial restraint about whether a court should decide the matter.

“He wasn’t expressing views on the merits [of Obamacare],” Jipping said. “ … If all you want is a judge who will strike down Obamacare, that is ironically how the left evaluates judges.”

4. ‘Hiding’ Information

Senate Democrats and some media outlets allege Republicans are trying to “hide” Kavanaugh’s past.

How transparent any single confirmation process should be is a matter of opinion decided by senators. But it may be worth considering what occurred with a previous Supreme Court nominee with some similar experience on her resume—Justice Elena Kagan.

Democrats are demanding more documents, largely from Kavanaugh’s time in the George W. Bush administration from 2001 to 2003, where he worked for the White House counsel’s office and as staff secretary to the president.

“If Republicans don’t want to review these documents, they don’t have to,” said Sen. Dianne Feinstein of California, the ranking Democrat on the Senate Judiciary Committee. “But it’s wrong to stand in the way of senators who want to review the full record.”

However, the George W. Bush Presidential Library is reportedly providing up to 1 million pages of documents for the Senate.

“I anticipate up to 1 million pages of documents from Judge Kavanaugh’s time in the White House counsel’s office and independent counsel’s office, along with records related to his 2006 confirmation to the D.C. Circuit,” Judiciary Chairman Charles Grassley, R-Iowa, said Tuesday on the Senate floor. “The production could be larger than the last five Supreme Court nominees combined. The other side is pretending like the most expensive and transparent confirmation process in history is not enough.”

Before being confirmed to the high court, Kagan was the Obama administration’s solicitor general, a key policymaking role—and far higher ranking than any post Kavanaugh held in the Bush White House.

Kagan also worked in the White House counsel’s office from 1995-1999, a controversial time for Bill Clinton’s presidency.

Nevertheless, during her Senate confirmation process, a comparatively smaller number of documents—170,000 pages—were provided regarding her work with Clinton. No senator asked for documentation regarding Kagan’s time as solicitor general for Obama.

“Everyone agreed that the documents were too sensitive for disclosure and could chill the candidness of internal deliberations,” Grassley said of Kagan’s solicitor general information. “This same respect for confidentiality should apply with greater force to staff secretary documents, which include some of the most sensitive policy advice going directly to the president.”

In the White House, the staff secretary oversees paper flow to the president, including comments from senior staff on documents the secretary has circulated.

Records from Kagan’s time as solicitor general would have been more relevant, Grassley said, since she had not been a judge until she joined the Supreme Court.

“Unlike the more than 300 opinions that Judge Kavanaugh authored and the hundreds more opinions that he joined in his 12 years of service on the D.C. Circuit, Justice Kagan had zero judicial opinions that she authored, zero judicial opinions that she joined, and zero years of judicial service,” Grassley said.

“Her solicitor general documents,” he said, “were therefore even more relevant.”