Supreme Court nominee Brett Kavanaugh on Wednesday refused to say whether a president could be subpoenaed — a critical issue in the ongoing special counsel probe of Russian election interference — calling the question “hypothetical.” But he said he had an “open mind” on the question of whether presidents can be sued.

Kavanaugh won't answer "hypothetical" of whether presidents must respond to subpoenas. pic.twitter.com/lRsNtCX5nY — TPM Livewire (@TPMLiveWire) September 5, 2018

Kavanaugh also said that U.S. v. Nixon, in which the Supreme Court ordered former President Richard Nixon to turn the Watergate tapes over to a federal court, was “one of the four greatest moments in Supreme Court history.”

In 1999, according to the Associated Press, Kavanaugh said that “maybe Nixon was wrongly decided” because the case “took away the power of the president to control information in the executive branch by holding that the courts had power and jurisdiction to order the president to disclose information in response to a subpoena sought by a subordinate executive branch official.”

On Wednesday, Kavanaugh said “I know there was a news story about that, and that’s just not a correct impression of my views.”