New Jersey Senator Cory Booker raised a fundamental concern with regard to Senate oversight of the Trump administration and its nominees Wednesday evening and Thursday, when he upended attempts to keep secret the records of Supreme Court nominee Brett Kavanaugh’s ruminations on racial discrimination. The Senate Judiciary Committee exchange that Booker provoked over the corrosive effects of official secrecy was consequential, not just in the hearing on Donald Trump’s high-court pick but in the history of a Senate where, too frequently, casual affronts to transparency have undermined the full functioning of the system of checks and balances.

The Senate is called on by the Constitution to provide “advice and consent” regarding presidential nominations of “judges of the Supreme Court.” This is an explicit charge that outlines a clear duty. Yet hundreds of thousands of pages of relevant records of Kavanaugh’s service to former President George W. Bush and former Vice President Dick Cheney have been withheld by the Trump White House under a bogus claim of executive privilege. Worse yet, the Republican majority on the Judiciary Committee has endeavored to keep troubling information that has been shared with the committee from being openly discussed as part of the confirmation process.

The absurd assertion that vital information may be taken out of circulation simply by stamping documents “Committee Confidential” is an affront to the values of openness and transparency that are essential to the work of the Judiciary Committee and the Senate. In an effort to constrain the inquiry into an exceptionally controversial nominee, the committee majority appears to have been using the “Committee Confidential” designation (which allows senators to review a document while preventing discussion of the document in a public hearing) to limit the ability of responsible senators to conduct an honest and complete examination of the Kavanaugh nomination.

Booker recognized this problem and objected. Then he acted, on Wednesday evening and through the day on Thursday, to reveal information that had been labeled “Committee Confidential.” He was condemned by conservatives for “grandstanding.” He was accused of making to big deal about releasing documents that were already been made public or that were in the process of being made public. He was attacked by senior Republicans who said he was making grand pronouncements to advance his own political agenda and ambitions.

But the bottom line is that Booker forced a debate about secrecy that needed to happen, got information that had been kept from the public into the open and jump started a process of releasing documents that should never have been classified as confidential.

In so doing, the senator offered a new model for resistance by engaged members of Congress to the Trump administration and its nominees.

Booker initially raised concerns related to an e-mail that had been labeled “Committee Confidential” on Wednesday evening and was admonished for doing so. He openly acknowledged that he violated Senate rules when he read portions of the e-mail while questioning Kavanaugh about his thinking with regard to racial discrimination. Booker’s office requested that key e-mails be declassified, and an attorney for former President Bush agreed overnight to that request.

Senators were still wrangling over the e-mail question Thursday morning, when Booker’s office circulated four documents that had previously been labeled “Committee Confidential,” including one that was particularly revealing with regard to the nominee’s thinking on racial issues that might come before the court.

The e-mail that Booker had read from during the exchange with Kavanaugh on Wednesday night was clearly relevant to the committee’s deliberations about a nomination for a place on the bench of a high court that frequently deals with cases that address discrimination. In it, Kavanaugh appeared to express concern, as a White House legal specialist serving during President Bush’s first term, about efforts to address circumstances in which “the government was deliberately indifferent to (rather than the cause of) the private discrimination.” He complained that such initiatives “might suggest an extraordinary expansion of governmental responsibility and liability for private racial discrimination.” Referring to Department of Transportation affirmative action regulations, Kavanaugh wrote in the 2001 e-mail, “The fundamental problem in this case is that these DOT regulations use a lot of legalisms and disguises to mask what in reality is a naked racial set-aside.”

Senators and citizens can debate the specific issues that are mentioned in the e-mail, and Kavanaugh’s response to them. But, surely, this is a debate that should be had as part of an examination of the nomination of the e-mail’s author to serve on a Supreme Court that weighs affirmative-action cases.

By any honest measure of senatorial duty, Booker was right to push for its release. Critics attacked the senator for referencing information contained in the e-mail and then for saying he would release it as an act of “civil disobedience.” They accused him of engaging in “histrionics” for talking about “knowingly violating the rules”—which stipulate that a senator who discloses confidential information may be punished with expulsion from the chamber—at a point on Thursday when the “Committee Confidential” designation had already been lifted.

But Booker kept on circulating “Committee Confidential” materials through the day on Thursday, with an announcement that “We will continue to release more committee confidential documents to draw attention to this sham process.”

The real “histrionics” on Thursday came from Judiciary Committee Republicans, who claimed that Booker was battling for transparency in order to advance a 2020 presidential run. “Running for president is no excuse for violating the rules of the Senate,” declared Texas Senator John Cornyn, a key Trump administration ally on the committee. Cornyn attacked Booker as “irresponsible and outrageous” and claimed that the Democrat’s referencing of the e-mail was “no different from the senator deciding to release classified information.”

Cornyn was wrong. This was different from releasing classified information of a sort that might involve national security or public safety. This was about examining a Supreme Court nominee’s written record with regard to issues that the court has considered and will again consider.

To their credit, Judicary Commmitte Democrats raced to Booker’s defense, expressing solidarity with their colleague. Illinois Senator Dick Durbin said: “Let’s jump into this pit together.” Senator Mazie Hirono (D-HI) focused attention on documents that revealed Kavanaugh’s belief that Native Hawaiian programs are Constitutionally questionable, noting that they, too, had been labeled “Committee Confidential.”

“I defy anyone reading this to be able to conclude that it should be deemed confidential in any way, shape, or form,” declared Hirono.

Senator Sheldon Whitehouse, a former state attorney general of Rhode Island, pointedly called out the Republican majority’s abuses of the “Committee Confidential” label, saying to his colleagues, “Lest silence imply consent, I think that rule is as ineffectual as if the chair had unilaterally repealed the law of gravity. It simply isn’t so. I haven’t agreed to this rule. I haven’t voted on this rule.”

It was Booker who took most of the heat, however. Indeed, he invited it. “As I’ve been saying from the beginning, this process has been a sham,” Booker announced Thursday morning. “The fact that tens of thousands of documents revealing a Supreme Court nominee’s views on key issues were deemed committee confidential and not available to the public reflects the absurdity of this process. The public has a right to access documents about a Supreme Court nominee’s views on issues that are profoundly important, such as race and the law. This process has demonstrated an unprecedented level of secrecy and opaqueness that undermines the Senate’s constitutional duty to advice and consent.”

(This article has been updated through the day with new details regarding the declassification of documents, and the wrangling over secrecy issues.)