GREENVILLE, N.C. — On matters like abortion, military spending and religion, Representative Walter B. Jones seems thoroughly in tune with this conservative, staunchly Republican district in eastern North Carolina, home to the Marine Corps’ Camp Lejeune and thousands of military retirees.

On the issue of war, however, Mr. Jones has defied typecasting. An early critic of the American invasion of Iraq, he has been ostracized by the Republican leadership in Congress. And now he is emerging as a leading advocate for swiftly withdrawing American forces from Afghanistan, a position that has made him, of all things, a liberal hero.

“When you talk about war, political parties don’t matter,” he said in an interview.

But Mr. Jones may no longer be the outlier he was six years ago. Late last month, an amendment intended to accelerate the withdrawal of American troops from Afghanistan sponsored by Mr. Jones and Representative Jim McGovern, Democrat of Massachusetts, nearly passed — in part because 26 Republicans broke with their leadership to support it, triple the number who voted for a similar measure last year. Their ranks included at least three freshmen elected with Tea Party support.

Some foreign policy analysts now see Mr. Jones, 68; Representative Ron Paul, Republican of Texas; and a small coterie of Tea Party stalwarts as the leading edge of a conservative movement to rein in American military power — a break from the muscular foreign policy of President George W. Bush.