FILE - In this March 31, 2015, file photo, Charles Krauthammer talks about getting into politics during a news conference in Corpus Christi, Texas. The conservative writer and pundit Krauthammer has died. His death was announced Thursday, June 21, 2018, by two media organizations that employed him, Fox News Channel and The Washington Post. He was 68. (Gabe Hernandez/Corpus Christi Caller-Times via AP, File)

NEW YORK — Charles Krauthammer, the Pulitzer Prize-winning columnist and pundit who helped shape and occasionally dissented from the conservative movement as he evolved from “Great Society” Democrat to Iraq War cheerleader to denouncer of Donald Trump, has died at age 68.

His death was announced Thursday by two longtime employers, Fox News Channel and The Washington Post. Krauthammer had said publicly a year ago he was being treated for a cancerous tumor in his abdomen and earlier this month revealed that he likely had just weeks to live.

“I leave this life with no regrets,” Krauthammer wrote in The Washington Post, where his column had run since 1984. “It was a wonderful life — full and complete with the great loves and great endeavors that make it worth living. I am sad to leave, but I leave with the knowledge that I lived the life that I intended.”

Sometimes scornful, sometimes reflective, he was awarded a Pulitzer in 1987 for “his witty and insightful” commentary and was an influential voice among Republicans, whether through his syndicated column or his appearances on Fox News Channel. He was most associated with Brit Hume’s nightly newscast and stayed with it when Bret Baier took over in 2009.

Krauthammer is credited with coining the term “The Reagan Doctrine” for President Reagan’s policy of aiding anti-Communist movements worldwide. He was a leading advocate for the Iraq War and a prominent critic of President Barack Obama, whom he praised for his “first-class intellect and first-class temperament” and denounced for having a “highly suspect” character.

Krauthammer was a former Harvard medical student who graduated even after he was paralyzed from the neck down because of a diving board accident, continuing his studies from his hospital bed. He was a Democrat in his youth and his political engagement dated back to 1976, when he handed out leaflets for Henry Jackson’s unsuccessful presidential campaign.

But through the 1980s and beyond, Krauthammer followed a journey akin to such neo-conservative predecessors as Irving Kristol and Norman Podhoretz, turning against his old party on foreign and domestic issues. He aligned with Republicans on everything from confrontation with the Soviet Union to rejection of the “Great Society” programs enacted during the 1960s.

“As I became convinced of the practical and theoretical defects of the social-democratic tendencies of my youth, it was but a short distance to a philosophy of restrained, free-market governance that gave more space and place to the individual and to the civil society that stands between citizen and state,” he wrote in the introduction to “Things That Matter,” a million-selling compilation of his writings published in 2013. As of midday Friday, the hardcover edition of “Things That Matter” Was No. 1 on Amazon.com. The paperback was No. 2.

For the Post, Time magazine, The New Republic and other publications, Krauthammer wrote on a wide range of subjects, and in “Things That Matter” listed chess, baseball, “the innocence of dogs” and “the cunning of cats” among his passions. As a psychiatrist in the 1970s, he did groundbreaking research on bipolar disorder.

He was attacked for his politics, and for his predictions. He was so confident of quick success in Iraq he initially labeled the 2003 invasion “The Three Week War” and defended the conflict for years. He also backed the George W. Bush administration’s use of torture as an “uncontrolled experiment” carried out “sometimes clumsily, sometimes cruelly, indeed, sometimes wrongly. But successfully. It kept us safe.”

And the former president praised Krauthammer after hearing of his death.

“For decades, Charles’ words have strengthened our democracy,” George W. Bush said in a statement. “His work was far-reaching and influential — and while his voice will be deeply missed, his ideas and values will always be a part of our country.”

Krauthammer was sure that Obama would lose in 2008 because of lingering fears from the Sept. 11, 2001 attacks, and foresaw Mitt Romney defeating him in 2012.

But he prided himself on his rejection of orthodoxy and took on Republicans, too, observing during a Fox special in 2013 that “If you’re going to leave the medical profession because you think you have something to say, you betray your whole life if you don’t say what you think and if you don’t say it honestly and bluntly.”