Sen. Ron Wyden said Thursday that it appears Supreme Court nominee Brett Kavanaugh lied to Congress in 2006 when he testified about when he learned of a post-9/11 surveillance program.

The Oregon Democrat said in an emailed statement to the Washington Examiner that documents published by the New York Times appear to contradict Kavanaugh’s testimony.

“Yes, the documents made public this week strongly suggest Brett Kavanaugh was involved in discussions about the Bush administration’s illegal warrantless wiretapping programs, and that he misled the American people in his 2006 testimony,” Wyden said.

“That kind of deception is unacceptable for someone who seeks a lifetime appointment to the highest court in the land,” said Wyden, a prominent critic of the National Security Agency's surveillance programs.

Kavanaugh testified during his 2006 confirmation hearing to serve on the U.S. Court of Appeals for the D.C. Circuit that he learned about “the president's NSA warrantless wiretapping program” when he read a December 2005 article in the New York Times.

"Did you see documents relating to the president's NSA warrantless wiretapping program?" Sen. Patrick Leahy, D-Vt., asked at the time.

Kavanaugh, who worked in the George W. Bush White House, told Leahy: "Senator, I learned of that program when there was a New York Times story — reports of that program when there was a New York Times story that came over the wire, I think on a Thursday night in mid-December of last year."

"You had not seen anything, or had you heard anything about it prior to the New York Times article?" Leahy asked.

"No," Kavanaugh said.

Leahy pressed him at the 2006 hearing: "Nothing at all?" Kavanaugh confirmed: "Nothing at all."

Kavanaugh was more equivocal Wednesday, telling Leahy he could not “rule anything out like that” when asked if he raised issues “about the constitutional implications of a warrantless surveillance program” with Bush administration lawyer John Yoo in 2001.

An email published Wednesday evening by the Times revealed that on Sept. 17, 2001, Kavanaugh emailed Yoo, asking if there were “any results yet” on the Fourth Amendment implications of “random/constant surveillance of phone and email conversations of noncitizens who are in the United States ... to prevent terrorist/criminal violence.”

The Bush-era program exposed in 2005 began shortly after the email exchange. It monitored the international phone calls of people inside the U.S. in an effort to prevent al-Qaida terrorism.

White House spokesman Raj Shah defended Kavanaugh's historical truthfulness, telling the Times his 2006 testimony was "entirely accurate" and that Kavanaugh's 2006 answer should be seen as whether he reviewed information about the program “as staff secretary," a job he took in 2003, after working in the White House counsel's office.

“The only controversial thing about this email is that it was leaked to the media, despite being ‘Committee Confidential,’ a violation of committee rules,” Shah said.

Wyden's statement is one of the most forceful responses yet. Leahy, for example, did not return to the subject when he had a second opportunity to question Kavanaugh on Thursday, though he did tweet, "We have discovered evidence that Judge Kavanaugh misled the Senate" in 2006 and about a separate matter in 2004 regarding leaked Democratic documents.

Lying to Congress is a federal crime, but rarely prosecuted. There's a five-year statute of limitations, meaning it may not be possible to charge Kavanaugh.

George Washington University law professor Jonathan Turley said that "at best, the answer is incomplete," though "such imprecision is often denounced as perjury but rarely prosecuted as perjury."

"In terms of influence [on] someone like Sen. Susan Collins, it would likely take a confession to flip a GOP vote," he said.

Turley said that Democratic allegations related to Kavanaugh's testimony "are undermined by their own tolerance for perjury in taking no formal action against figures like James Clapper," the former director of national intelligence, who avoided potential charges this year for admittedly inaccurate testimony about NSA surveillance.

Kavanaugh's stance on NSA mass surveillance has not received significant attention during his confirmation hearings, despite public scrutiny of a 2015 opinion in which he upheld the bulk collection of U.S. call records, a program that replaced presidentially mandated collection that began in 2001.

According to a 2014 report from the Privacy and Civil Liberties Oversight Board, "[f]rom late 2001 through early 2006, the NSA collected bulk telephony metadata based upon presidential authorizations issued every thirty to forty-five days. In May 2006, the [Foreign Intelligence Surveillance Court] first granted an application by the government to conduct the telephone records program under Section 215 [of the Patriot Act]."

Criticism of the NSA's now-discontinued call record dragnet and earlier surveillance programs was bipartisan, but Republican critics including Sens. Rand Paul, R-Ky., and Mike Lee, R-Utah, support Kavanaugh's nomination, which is expected to be approved in a majority vote.