The conservative commentator — and celebrated Catholic convert — has lost his battle with brain cancer.

From the Washington Post:

Robert D. Novak, 78, an influential columnist and panelist on TV news-discussion shows who called himself a “stirrer up of strife” on behalf of conservative causes, died today at his home in Washington of a brain tumor first diagnosed in July 2008.

Novak’s “Inside Report” syndicated column, shared for 30 years with the late Rowland Evans, was important reading for anyone who wanted to know what was happening in Washington. Novak and Evans broke stories about presidential politics, fiscal policy and inter-party feuds. Their journalism, which reported leaks from the highest sources of government, often had embarrassing consequences for politicians.

In recent years, Novak was best known for publicly identifying CIA operative Valerie Plame. His July 14, 2003, column was printed days after Plame’s husband, former U.S. ambassador Joseph C. Wilson IV, publicly claimed the Bush White House had knowingly distorted intelligence that Iraq tried to obtain uranium from Africa.

The column triggered a lengthy federal investigation into the Plame leak and resulted in the 2007 conviction of a top vice presidential aide, I. Lewis “Scooter” Libby, for perjury and obstruction of justice. Bush later commuted Libby’s prison term.

Novak was accused by prominent journalists of being a pawn in a government retribution campaign against Wilson. Novak, who had called the U.S. invasion of Iraq “unjustified,” denied the allegation.

He wrote that his initial column was meant to ask why Wilson had been sent on a CIA fact-finding mission involving the uranium. Then-Deputy Secretary of State Richard L. Armitage mentioned Plame’s CIA position to Novak, and Bush aide Karl Rove confirmed it.

In a 2006 column, Novak wrote Armitage “did not slip me this information as idle chitchat. . . . He made clear he considered it especially suited for my column.” Armitage told The Washington Post that his disclosure to Novak was made in an offhand manner and that he did not know why Plame’s husband was sent to Africa.

Novak lamented the Plame story would “forever be part of my public identity” despite having written columns he said were more important.

Until the Plame controversy, Novak had largely been known as a strong anti-Communist in his foreign policy views. He also was an leading advocate of supply-side economics, a belief that tax cuts would lead to widespread financial prosperity.

David Keene, chairman of the American Conservative Union lobbying organization, said that Novak helped transform supply-side economics from a fringe idea into a tenet of President Ronald Reagan’s economic policy. Keene called Novak “a giant of the profession” who “gave respectability and visibility to conservative ideas and positions in the 1970s, when they were mostly dismissed.”

Novak was a congressional reporter for the Associated Press and the Wall Street Journal before he teamed with Evans in 1963 to write a Washington-based political column for the old New York Herald-Tribune. “Inside Report” ran in almost 300 papers nationally, including The Post. Novak continued the column after Evans’s retirement in 1993. Evans died in 2001.

Focusing on political intrigue rather than starchy analysis, they had an immediate effect with news about Sen. Barry Goldwater’s (R-Ariz.) likely nomination as the Republican presidential candidate in 1964.

The Goldwater story led a Newsweek profile about the duo that helped shape their formidable reputation. But as Novak wryly noted, the Newsweek account was written by his close friend Michael Janeway.

“Little in Washington is on the level,” Novak wrote in his 2007 memoir, “The Prince of Darkness,” which had long been his nickname.

Meantime, Novak wrote about his conversion in that same memoir:

Novak was born Jewish and attended Christian services sporadically until the mid-1960s, after which he stopped going to religious services for nearly 30 years. But Novak said the Holy Spirit began to intervene in his life.

A friend gave Novak Catholic literature after he came close to dying from spinal meningitis in the early 1980s. About a decade later, the columnist’s wife, Geraldine, also not a Catholic, persuaded him to join her at Mass at St. Patrick’s Catholic Church in Washington. The celebrant was a former source of Novak’s.

Father Peter Vaghi, now Msgr. Vaghi and pastor of the Church of the Little Flower in Bethesda, Md., was a former Republican lawyer and adviser to Sen. Pete Domenici, R-N.M. He had been a source for the Evans and Novak column that Novak wrote with Rowland Evans.

Novak started to go to Mass regularly, but it wasn’t until a few years later that he decided to convert to Catholicism. The turning point, as he recounts in his book, happened when he went to Syracuse University in New York to give a lecture. Before he spoke, he was seated at a dinner table near a young woman who was wearing a necklace with a cross. Novak asked her if she was Catholic, and she posed the same question to him.

Novak replied that he had been going to Mass each Sunday for the last four years, but that he had not converted.

Her response – “Mr. Novak, life is short, but eternity is forever” – motivated him to start the process of becoming a Catholic through the Rite of Christian Initiation of Adults. He was baptized at St. Patrick’s Church in 1998. His wife was also baptized a Catholic.

Novak said he believed the Holy Spirit led him to Catholicism. He told an audience at the Heritage Foundation in Washington Aug. 2 that when he was interviewed by The New York Times about his book the interviewer scoffed at his story about his source turned priest.

But Novak said he told her he believed the Holy Spirit was behind the coincidences.

“I consider this the only one true faith, so I believe the Holy Spirit led me to it,” Novak said. “Then the next day Pope Benedict (XVI) said the same thing.”

May his soul, and the souls of all the faithful departed, through the mercy of God, rest in peace.