JOHN SUNUNU, who never suffered fools and was no respecter of persons, was ousted from the White House in the end by the force of his own personality.The word "abrasive" has followed him through three years in Washington as the chief of the president's staff. Under the intense pressures of a static economy, plunging presidential popularity, and a lurching domestic policy picture, the chief of staff found he had made more enemies than friends. His probable successor, Illinois lawyer Samuel Skinner, has been a much smoother operator as secretary of transportation. Governor Sununu's departure is setting off alarms for conservatives. He has been considered a strong conservative force in White House policy, even though the chief of staff role must retain something of the honest broker about it. Mr. Skinner is viewed as more pragmatic than conservative, much like President Bush himself. Some conservatives, in fact, see Sununu as a mere scapegoat. He was blamed for muddled policy signals on the economy, for example, because the president has not stepped in to settle disputes and set direction. Sununu has caught flak for blocking tax cuts in recent weeks, says Gary Bauer, president of the Family Research Council and domestic policy adviser in the Reagan White House, but "if the president wanted a tax cut, he'd get one." "My suspicions are that people got angry with Sununu because they wanted to avoid being angry with the president," says Mr. Bauer. Contrast the disarray in the White House in recent weeks to the calm accompanying the start of the Gulf war a year ago. Top Bush administration officials disagreed over how to deal with Iraq, but the president ended the strife with clear-cut statements of policy and direction. Concerning the economy, the disagreement between top administration officials has grown increasingly public in recent weeks, while the president appears to be whipsawed by conflicting advice. Sununu may have been more than a scapegoat for Bush's difficulties, however. His own weaknesses, and his blindness to them, made him a ready target. His lavish use of military planes, corporate jets, and his government car and driver broke no laws or ethics codes, but his excesses absorbed the attention of the White House press for weeks last spring and blocked out other messages. The difficult side of Sununu was revealed during one of the president's more damaging missteps recently. Bush made a speech in New York that called for banks to lower interest rates on credit cards. After the Senate escalated that call into a legal ceiling on rates the next day, the stock market plunged 120 points. Reportedly, Sununu penned into the speech the lines about credit-card interest without consulting any other staff members. The idea had been discussed casually at a White House meeting on political messages, not one on economic policy. When his role was reported in the Washington Post, Sununu lashed out at the reporter at a public event, calling the story "a lie." Later he denied calling the reporter a liar. Was he making a technical distinction, for combative purposes, between calling the story a "lie" and calling the reporter a "liar"? Was he simply denying an episode that was witnessed by several reporters in the crowd? More important was whether the story was, in fact, a "lie." Sununu went on to claim in a television interview that the president ad-libbed the credit-card comment. Whether this was the plain truth, a falsehood, or a coy evasion, it served to shift blame from his own embattled brow to that of the president. James Pfiffner, a George Mason University professor who has researched the chief-of-staff role, was "amazed" that Sununu would deflect blame onto the president, whether accurately or not. It's one sign of a chief of staff who has become a negative force in the administration, he says. Sununu has been one of the most powerful men in Washington. He manages a White House where decisions are made by an elite few. On domestic affairs, Sununu and budget director Richard Darman personally negotiated many major deals with Congress. Colleagues have marveled at his sheer mental capacity in juggling complex political issues throughout the day. White House staff members have learned to research and analyze carefully before presenting ideas, or risk a merciless public critique. Congressional leaders and Cabinet members, however, sometimes did not take such treatment well. Ideally, a chief of staff is an honest broker who brings well-sounded policy options to the president. Sununu will be missed by many conservatives and his successor welcomed by many Sununu opponents because both his allies and combatants saw him as more than an honest broker. "It's no secret that he had strong opinions on global warming and other environmental issues," says Fred Krupp, executive director of the Environmental Defense Fund. m hopeful that the administration will be able to move more aggressively and assertively now."