Historian, author and journalist Michael Ledeen is in line to be a special adviser to Secretary of State Alexander M. Haig Jr., with emphasis on dealing with international terrorism.

Haig is said to be unhappy with the U.S. intelligence community's suggestion -- counter to his own beliefs -- that no convincing evidence links the Soviet Union to the support of international terrorists. Ledeen's imminent appointment is seen as a way to give the administration's anti-terrorist thrust a boost.

But Ledeen, the executive editor of The Washington Quarterly, isn't all that thrilled at the idea of being Haig's main man for terrorism. He sees the job as diplomatic in nature, and his role as that of a general trouble-shooter.

Not that he disagrees with Haig on the subject of Soviets and terrorists: in a recent article written with novelist Arnaud de Borchgrave for The Post, Ledeen wondered why western intelligence was "so unwilling to produce the evidence they possess" of an active Soviet role in international terrorism.

"We can sympathize with the desire of American officials to keep such evidence classified," the article said. "But we cannot understand their recent suggestion that no such evidence exists."

Ledeen is expected to share an office at State with Vernon Walters, another Haig adviser, though he'll report directly to the secretary.