Although he had covered the 1991 Gulf War for The New Republic and had subsequently edited both that periodical and The Atlantic Monthly, Michael Kelly was perhaps best known for the series of columns he contributed to The Washington Post. Those who met Kelly were always astonished by the stark contrast between the mild and courteous manner of the man, and the virulence of his journalistic invective when it was trained on his favourite target — American liberalism.

Bill Clinton, along with what Kelly regarded as the moral bankruptcy to which he had brought the American presidency, was a regular focus for his spleen. In column after excoriating column he attacked Clinton, and, by extension, Democrats in general. As such he was not a characteristic figure in American mainstream journalism, being entirely at odds with the liberal ethos that has so long pervaded the American “thinking” press. Among his bêtes noires were such venerable names in the literary Pantheon as those of Norman Mailer and Kurt Vonnegut Jr, with their Sixties consciences and their scepticism about the rectitude of the American cultural, economic and military juggernaut.

Before becoming a opinion-maker Kelly had been a highly respected reporter. It was his desire to return to the narrative depiction of events that led him back to reporting, and to his death in Iraq.

Michael Kelly was born in Washington in 1957 into an Irish-American family with journalism in its blood. His mother, Marguerite Kelly, wrote the syndicated column Family Almanac. His father, Thomas Kelly, was a reporter for The Washington Star.

In Washington, Kelly was educated at Gonzaga College High School from where he went to the University of New Hampshire, graduating in 1979. From there he went to ABC as a researcher on Good Morning America before beginning on newspapers as a reporter on The Cincinatti Post. There, his reporting and investigative work gained him awards from the Associated Press, Sigma Delta Chi and United Press International.

In 1986 he moved to The Baltimore Sun, soon moving back to his home town as the paper’s Washington correspondent. Among his assignments were the election campaigns of Jesse Jackson and Michael Dukakis, and it was on the latter that he met his future wife, Madelyn, a producer for CBS.

When she went as a producer to the Gulf War he made sure he found himself an assignment there, too, freelancing for The New Republic. This made his name. Keeping his distance from reporting pools and official spokesmen, he turned in what were generally agreed to be the most informed and impartial accounts of the campaign.

He stayed in the country after the defeat of Iraq, continuing to file reports on the situation in the Kurdish areas and the mood in Baghdad. His dispatches earned The New Republic the 1991 Ed Cunningham Memorial Award from the Overseas Press Club and a National Magazine Award in 1992.

The book arising out of these pieces, Martyr’s Day: Chronicle of a Small War (1992), won him the 1992 Martha Allbrand Award for non-fiction from PEN, the writers’ fellowship.

In that year Kelly joined The New York Times as its Washington correspondent and covered the presidential election campaigns of Ross Perot and Bill Clinton. In 1994 he spent the summer in the Gaza Strip, where he wrote a cover story on Yassir Arafat’s Palestinian regime for The New York Times Magazine.

At home he had remained unrelenting in his attacks on the Clinton administration, and it was regarded as highly eccentric when, in 1996, he was appointed Editor of The New Republic, whose proprietor was Martin Peretz, a close acquaintance of the Vice-President, Al Gore. As Editor, Kelly did not a whit abate his onslaught on the Clinton presidency, and his editorship did not see out 12 months. In the autumn of 1996 he found another vent for his views when he became a columnist for The Washington Post. This provided a vehicle for some of his most memorable sallies.

His second editorship was no less surprising than his first had been — this time the liberal The Atlantic, which had not long before been acquired by the Washington businessman David Bradley. Both at The Atlantic and The New Republic Kelly was greatly liked by his staff, to whom he was loyal, even while determining to do things his way.

Kelly joined The Atlantic in 1999 and set about changing its view of America’s political and literary culture, both through his own robust counterblasts to liberalism and by getting on board a handful of right-wing writers of his own kidney. Within three years The Atlantic, too, had garnered a sheaf of awards.

But Kelly had begun to feel that he wanted to get back to basic reporting, and last year he left the day-to-day running of the magazine, becoming editor-at-large. When the American expeditionary force began to be assembled to attack Saddam Hussein’s regime he arranged to file dispatches for The Washington Post. This time, he deliberately turned his back on his former independent stance, since he wanted to report the day-to-day life of a unit in combat. As such he became an “embedded” correspondent with the US 3rd Infantry Division in Iraq, with the idea of producing a chronicle of its progress to become a book.

Kelly and the American soldier driving him were killed when the US Army Humvee in which they were travelling south of Baghdad airport came under fire, left the road and rolled into a canal.

Kelly is survived by his wife, and by two sons.

Michael Kelly, journalist, was born in Washington on March 17, 1957. He was killed in a vehicle accident in Iraq on April 2, 2003, aged 46.