WASHINGTON — Senate Minority Leader Chuck Schumer is ramping up Democrats' efforts to obtain documents involving Supreme Court nominee Brett Kavanaugh by asking former President George W. Bush to release mountains of files from the judge's time in the White House.

The New York Democrat wrote in a letter to Bush, released Friday and obtained by NBC News, that he understands the former president's support for Kavanaugh and acknowledges their difference of opinion on whether he's the right person to serve on the high court.

But Schumer said he was reaching out "to ask you to authorize that the complete record of Judge Kavanaugh's service in the White House be made public so that all Americans can be informed about this nomination and the Senate can fulfill its constitutional advice and consent obligations."

Read Schumer's letter here

Senate Republicans are aiming within weeks to hold a confirmation hearing for Kavanaugh, nominated by President Donald Trump earlier this month, and to confirm him before the next Supreme Court term begins in October. Kavanaugh has been serving as a judge on the U.S. Court of Appeals for the District of Columbia Circuit since 2006 and previously served as staff secretary to Bush from 2003 to 2006.

Schumer pointed out that when the Senate considered President Barack Obama's 2010 nomination of Justice Elena Kagan, lawmakers from both parties asked the National Archives and the Clinton library to provide all documents related to Kagan's service in the White House under former President Bill Clinton and those papers were ultimately released.

Republicans, however, have now "declined to sign a bipartisan document request or Judge Kavanaugh's complete record,” wrote Schumer, who said he's concerned that only those documents that have been "pre-screened and approved by the private legal team" will be disclosed to the Senate.

Later Friday, Senate Judiciary Committee Chairman Sen. Chuck Grassley, R-Iowa, said he requested special access to documents related to Kavanaugh’s legal work in the White House, and said the Democratic ranking member on the committee, Sen. Dianne Feinstein, D-Calif, ignored his requests for a joint request.

"The Minority rejected out of hand multiple accommodations that I’d offered to assist in targeting material they believe is relevant,” Grassley said in a statement. “Instead, they demanded that we expand the request to require a search of every email from every one of the hundreds of White House staffers who served alongside Judge Kavanaugh for nearly six years, to find records that merely mention his name.”

Schumer hit back, and said Republicans refused to request critical documents. "This deliberately selective request leaves out what may be the most important thing in Judge Kavanaugh’s record: his time as White House Staff Secretary. What are Republicans hiding in Judge Kavanaugh’s record?" Schumer said in a statement.

Among other things, the documents could shed light on whether Kavanaugh misled Congress more than a decade ago when he was considered for his current job on the court. At the time, he denied under oath that he had anything to do with crafting the Bush administration's terrorism detainee policy. Sens. Dick Durbin, D-Ill., and Patrick Leahy, D-Vt., alleged at the time that Kavanaugh may have misled Congress.

The Department of Justice said there was not enough evidence that proved Kavanaugh gave false statements to Congress.

Earlier Friday, Feinstein wrote to the National Archives objecting to its decision not to release documents related to Kavanaugh's service in the Bush White House.

"I have been on the Committee for more than twenty years and have been involved in ten prior Supreme Court nominations," she wrote. "This has never happened before, and a biased denial of document requests to one half of the Committee is unsupported by the law and impedes the minority's ability to discharge its constitutional obligation to provide advice and consent."