n. Writers and other members of the intelligentsia who advocate war or imperialism.
How the war fevers raged in those days after Sept. 11. The nation's syndicated belligerati were beside themselves. Columnist Michael Kelly flayed the unconscionable pacifists as pro-terrorist and evil. Charles Krauthammer argued for bombing an enemy city, anywhere.
—Michael Powell, “An Eminence With No Shades of Gray,” The Washington Post, May 05, 2002
[F]ormer critics of imperialism found themselves trapped by the debris of September 11. Many have now become its most vociferous loyalists. I am not, in this instance, referring to the belligerati — Salman Rushdie, Martin Amis and friends — ever-present in the liberal press on both sides of the Atlantic.
—Tariq Ali, “The new empire loyalists: Former leftists turned US military cheerleaders are helping snuff out its traditions of dissent,” The Guardian, March 16, 2002
2001 (earliest)
The poster behind the "Preferred User" nickname is a member of the belligerati (those who seek to wage war for war's sake or for profit).
—Alan Marr, “Note to Chinese Americans…,” alt.politics.democrats, April 10, 2001