White House Chief of Staff John H. Sununu, the target of sharp and often bitter complaints by fellow Republicans, yesterday defended his often contentious performance and said his leadership on domestic issues gave President Bush a year of triumph over the Democrats.

"Contrary to a lot of what has been written and talked about," Sununu told a National Press Club audience, the past year has been "a very successful year in terms of agenda set and agenda fulfilled for the president."

Asked whether his highly publicized fights with members of Congress, party figures and other Republicans did not end up hurting the president, Sununu replied, "If the situation were as described, I assure you, we would not have been able to put together the first multi-year budget and have the success in areas such as clean air, child care and across the board."

Sununu described his battles as solely aimed at protecting Bush from "gratuitous" shots and his legendary temper as used only for effect. "I guarantee you that contrary to the legend, any strong statements on my part are both controlled, deliberate and designed to achieve an effect. There is no random outburst. It all is designed for a purpose. And I think the efficiency of the result is underscored by what we've been able to achieve."

The chief of staff said, "I make no apologies for feeling that the president of the United States ought not to be subjected to inappropriate attacks without somebody willing to . . . comment both in the context and in the tenor of the original charge. . . . You have never seen me initiate an attack."

Sununu's problems, however, have been with Republicans more than with Democrats. Numerous House Republicans have complained privately and publicly about the former governor's treating them with arrogance and disdain and about his failure to understand their political and institutional problems, work with them on legislation and political issues, and assess the mood and inclination of Republicans in Congress in mapping legislative strategy.

As recently as Monday, Sen. Phil Gramm (R-Tex.), the newly elected head of the National Republican Senatorial Committee, hosted a lengthy session with top GOP officials and advisers from which Sununu was excluded in order to encourage broad discussion without feuds provoked by the chief of staff, sources said.

In his talk, Sununu said Bush would promote a limit on terms in Congress, a change that would require a constitutional amendment. The 1988 GOP platform, which Bush controlled, called for such a limit, and both he and Vice President Quayle endorsed a limit before the last election. But the administration has never formally proposed or pushed the idea.

Sununu touted the budget agreement reached last October, and he returned to an early White House defense of Bush's decision to renege on his pledge not to increase taxes. "It was a payment of ransom {to the Democrats} to save this country's economy," Sununu said, adding that Bush "was forced to pay the tax ransom once. . . . He will not be forced to pay the tax ransom again."

Sununu blamed the Democrats for a six-month delay in getting the $500 billion deficit-reduction deal passed and suggested that that delay caused some of the problems evident in the economy today. Turning sharply partisan, he also said the Democrats were looking for an excuse to raise taxes and would use the Persian Gulf crisis as that excuse.

The costs of the crisis have been sharply escalating. Those costs were kept "off-budget" in the budget agreement because of their uncertainty, but some Democrats have suggested that the costs should be fully reflected in the new budget and that a surtax of some sort may be needed to pay them. Democrats, Sununu said, are "looking for a cause to justify it, whether it is a surtax on the war."

Sununu outlined a broad agenda for Bush that will include some variation of capital gains tax cuts and other economic growth "components" to be announced in the Jan. 29 State of the Union address, and he suggested that the upcoming session of Congress will be more partisan and involve more battles than the last.