Washington ? Political columnist Robert Novak, a conservative, pugilistic debater and proud owner of the “Prince of Darkness” moniker, died Tuesday after a battle with brain cancer that was diagnosed in July 2008. He was 78.

His wife of 47 years, Geraldine Novak, told The Associated Press that he died at his home in Washington early in the morning.

A household face as co-host of CNN’s “Crossfire,” Novak had been a columnist for the Chicago Sun-Times for decades.

“He was a Washington institution who could turn an idea into the most discussed story around kitchen tables, congressional offices, the White House, and everywhere in between,” Senate Republican leader Mitch McConnell of Kentucky said in a statement.

Said House Republican Leader John Boehner of Ohio: “Bob made remarkable contributions in the field of journalism and to the American political landscape.”

In recent years, Novak ended up actually being a part of a big Washington story, in ways he likely never intended, becoming a central figure in the Valerie Plame CIA leak case.

Novak was the first to publish the name of the CIA employee, and he came under withering criticism and abuse from many for that column, which Novak said began “a long and difficult episode” in his career.

“I had a terrific time fulfilling all my youthful dreams and at the same time making life miserable for hypocritical, posturing politicians and, I hope, performing a service for my country,” Novak wrote in his memoir, “The Prince of Darkness: 50 Years Reporting in Washington.”

Actually Novak had been dubbed the “prince of darkness” by a journalist friend early in his career, and he embraced it. He wrote in that 2007 memoir that he became proud of the label derived from his “unsmiling pessimism about the prospects for America and Western civilization.”

“He loved being a journalist, he loved journalism, he loved his country and his family,” Geraldine Novak told the AP.

Novak, editor of the Evans-Novak Political Report, is perhaps best known as a co-host of several of CNN’s political talk shows, where he often jousted with liberal guests from 1980 to 2005. One of the best-known was “Crossfire.”

While he became known as a conservative for his role on “Crossfire” and other CNN political shows like “The Capital Gang,” he differed with conservatives on many issues, expressing doubts about invading Afghanistan and frequently criticizing the war in Iraq.

Novak wrote in his book about often giving politicians the choice of being a source or a target, a strategy that often produced scoops for his column.

With a lengthy list of highly placed sources, a high public profile and a relentless approach to reporting his column, Novak produced many scoops.

Among those scoops: a 2003 column in which he outed Plame as a CIA agent. The article was published eight days after Plame’s husband, Joseph Wilson, said the Bush administration had twisted prewar intelligence to exaggerate the Iraqi threat of nuclear weapons.

Citing two Bush administration officials, Novak revealed Plame worked for the CIA on weapons of mass destruction. That blew her cover as a CIA operative and led to the investigation of who leaked that information, and eventually to the conviction of I. Lewis “Scooter” Libby, Vice President Dick Cheney’s former chief of staff, on charges of perjury and obstruction of justice for lying to investigators about his conversations with reporters about Plame.