Ford Rowan . . . NBC New's Pentagon correspondent for the past 18 months . . . has resigned over what he considers the network's "irresponsible journalism" in airing a half-hour interview with an American hostage in Tehran on Monday night . . .

The failure of NBC to include his own two minute interview with State Department spokesman Thomas Reston sometime during the initial half-hour program that night apparently triggered the resignation . . . which Rowan wrote early Tuesday morning after "sleeping on the decision" . . .

The Reston interview, presenting the U.S. government's response, was included in a late night, one-hour special on NBC that same night . . . some 2 1/2 hours after U.S. Marine Cpl. William Gallegos' taped interview from the besieged embassy in Tehran . . .

Rowan emphasized yesterday that he "didn't want to add [his] voice to the cheap shots that people have been taking at NBC New's since the interview . . . and "I didn't want to be perceived as going public with my complaints."

But work of his resignation . . . which he mailed to NBC News president William Small Tuesday morning along with a copy to bureau chief Sid Davis . . . began to surface later in the day and Rowan eventually posted a notice on the bureau bulletin board confirming that he'd quit . . .

Rowan declined to elaborate on his resignation letter but friends familiar with the memo say that he complained to Small that the broadcast was a violation of journalistic ethics . . . that NBC had given up too much editorial control over the interview . . . had permitted the "so-called students" to manipulate NBC's coverage . . . had given them a prime-time propaganda platform and that NBC News had "become a pawn of terrorists" . . .

Rowan said yesterday "it was irresponsible to run (the interview) and not include the U.S. response" . . .

Rowan said he "very much regretted" that his resignation had become public at this time . . .

"The game plan was for me to stick to the job at least into the first of the year . . . there's no telling when something big is going to break on the Pentagon beat . . . and then maybe after I'd left I might have written an article for the Columbia Journalism Review or something . . . .

"I don't want to desert during the crisis . . . and I didn't want my arguments to come out until after the political bull---- was out of the way .ar. . . ."

Rowan, who has been with NBC for five years, said "our relations have been very smooth . . . I just happen to disagree on this one point and if you believe in something you should act" . . . .

Rowan told us yesterday that he had taped the two-minute interview with Reston (Hodding Carter was out of town that day) earlier Monday and had made "repeated calls to producers here and in New York to argue that you've got to run two minutes of the government's point of view . . . if you're going to run 30 minutes of the terrorists and their hand-picked hostage . . . ."

Davis said yesterday that correspondant John Chancellor did "incorporate the gist" of Reston's view in the half-hour show but that it was a producer's decision . . . a judgment call subject to a very tight time frame for the 30-minute telecast . . . .

Small said late yesterday he has not received Rowan's letter but when told of its apparent thrust, he commented: "No one at NBC News is required or expected to agree with all our editorial judgments . . . we welcome criticism from within as well as from outside NBC News. . . .

"Ford Rowan is a good correspondant and we regret that he felt moved to make a dramatic public gesture beyond voicing his views to his colleagues." . . .

Davis declined to discuss the resignation except to note it was to take effect in the middle of February . . . but he strongly defended NBC News and the Gallegos interview. . . . .

"It was good journalism," said Davis . . . "We told everybody right up front about our negotiations with the Iranians . . . what we were going to do . . . we leveled wih everybody."

"I think NBC was right in what it did . . . I think when a person resigns the reasons for his resignation are his personal reasons and I don't talk about them." . . .

Other sources at NBC News said that the 36-year-old Rowan, an attorney, had indicated to the network earlier this year that he was thinking of leaving journalism to start a law practice . . . and is reportedly working without a contract at this time . . . .