Senate Minority Leader Chuck Schumer, D-N.Y., sent a letter to former President George W. Bush on Friday calling on him to authorize the release of records stemming from Supreme Court nominee Brett Kavanaugh’s time working in the White House.

Schumer’s request of Bush is the latest escalation in the dispute between Senate Republicans and Democrats over the disclosure of documents related to Kavanaugh’s time working for Bush, and specifically those pertaining to his time as staff secretary.

“You have been an advocate of transparency regarding your presidential records, and you have previously taken steps to make portions of your library’s collection of White House documents more available to the public,” Schumer wrote to Bush. “I believe that making Judge Kavanaugh’s complete record is consistent with your commitment to transparency and is strongly in the public interest.”

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Trump nominated Kavanaugh, a judge on the U.S. Court of Appeals for the District of Columbia Circuit, to replace retiring Supreme Court Justice Anthony Kennedy on the high court this month, and his selection kicked off an intense confirmation fight.

The scope of Kavanaugh’s White House documents to be released to the public has emerged as a key point of contention for Democrats and Republicans.

Senate Judiciary Committee Chairman Chuck Grassley, R-Iowa, said in a letter to Schumer on Wednesday that he expects the committee will receive up to 1 million pages of documents stemming from Kavanaugh’s tenure in the White House and believes Kavanaugh’s confirmation will be the “most transparent in history.”

But he argued the records related to Kavanaugh’s time as staff secretary are not relevant to evaluating his fitness for a spot on the Supreme Court.

Grassley characterized Democrats’ efforts as a “fishing expedition” designed to “obstruct the confirmation process.”

Republicans are aiming to confirm Kavanaugh by Oct. 1, the first day of the Supreme Court's next term.

But in his letter to Bush, Schumer said the release of Kavanaugh’s full record is necessary “so that all Americans can be informed about this nomination and the Senate can fulfill its constitutional advice and consent obligations.”

“While the country may be divided on whether Judge Kavanaugh should join the Supreme Court, there ought to be no disagreement on whether the process that leads to a confirmation vote should be a fair and impartial one,” Schumer said.

Trump’s nomination of Kavanaugh earned Bush’s acclaim. The 43rd president said Trump made an “outstanding decision” in selecting Kavanaugh, who he called a “brilliant jurist.”