CEDAR RAPIDS, IOWA, FEB. 5 -- The nasty battle for the GOP presidential nomination centered today on which of the leading candidates is the meaner: Sen. Robert J. Dole (Kan.), for one-liners suggesting his chief opponent has done nothing in office, or Vice President Bush, for letting subordinates criticize Dole and then asserting ignorance about the attack.

Dole, no neophyte at hardball campaigning, lashed out at Bush and the news media here today. The senator appeared to be struggling to prevent the combat with Bush and continuing disclosures about a government loan to a former aide from drowning out his basic message -- that he represents the traditions of small town America and that Bush does not.

Bush, campaigning in South Dakota, said the latest spat had become "a little diversionary" to his message as well. He continued to dodge questions about his responsibility for remarks made this week in a news release by his Iowa chairman, George Wittgraf, who accused Dole of "cronyism" and of sinking the GOP ticket in 1976.

Both candidates appeared to be exaggerating their outrage in the final days before the Iowa caucuses. Bush portrayed himself as the injured party who never criticizes Dole, when in fact he has been targeting Dole all week through surrogates. Dole also played the role of victim, saying that Bush owes "my wife an apol- ogy . . . " Dole claimed "we haven't made any mean, personal attacks on anyone in his {Bush's} family or on him."

The "mean, personal attack" on Elizabeth Hanford Dole that the senator referred to appeared to amount to one paragraph in a news release issued Wednesday by Bush aide Wittgraf, which said, " . . . three federal agencies are examining aspects of Elizabeth Hanford Dole's now defunct blind trust." The only other reference to the Doles as a couple noted they are wealthy and live in Washington's Watergate complex.

Bush said he would "absolutely not" apologize for Wittgraf, whom he described as having gotten "tired of all the negative attacks on me" by Dole. He referred reporters to an eight-page summary of Dole quotations in recent months about Bush, including: "I can't just fly off like the vice president; some of us have work to do," and "Agriculture is not his strong suit. I don't know what is, but it's not agriculture," and "I'm a little disadvantaged {in campaigning} because I have to work for a living. The vice president has nothing to do."

Dole, who charged Bush with "groveling in the mud" and "below-the-belt" campaigning, has himself a history of tough, if not nasty, attacks on opponents. In the 1976 vice presidential contest, he denounced the Democratic Party for its history of initiating "Democrat wars." In his 1974 Senate campaign, his opponent, Dr. Bill Roy, complained bitterly that Dole's campaign had accused him of being an "abortionist on demand."

In today's exchange, both Dole and his Iowa chairman, Sen. Charles E. Grassley (R-Iowa) expressed outrage over attacks on Elizabeth Dole. "I think particularly the attacks on Mrs. Dole are unwarranted and the lowest level a campaign can take in the state of Iowa," Grassley said.

Throughout the day, Dole and Grassley attempted to deflect continuing questions about a controversial Small Business Administration loan to former Dole aide John Palmer that government agencies are investigating.

"The media, led by the Bush campaign, intimidated by the Bush campaign, has been beating itself on nothing," Dole said, telling reporters, "It won't go away because you keep talking about nothing. . . . Somebody writes it and then everybody reports it. Nobody checks the facts. There aren't any facts. There is nothing there. . . . There is nothing improper about it. I didn't lean on anybody."

For Bush, the latest tangle with Dole also produced some awkward moments. The vice president has spent most of this week telling campaign audiences that his chief qualification is "executive leadership" and the ability to make decisions, unlike the stalling and compromising of Congress. But today, Bush also was saying he had no idea what one of his top campaign strategists was doing in a news release that bore his national campaign letterhead.

He said, "Frankly, I haven't read the whole statement on it and I don't intend to do it." He added, "I didn't know he was making this attack."

In fact, Wittgraf reports directly to Bush's top campaign strategists and his statement was issued with their consent. The vice president said he would not endorse Wittgraf's criticism, would not "back away" from it, and would not "characterize it one way or the other."

The Wittgraf statement was only one part of a deliberate effort in recent days by the Bush campaign to have subordinates engage in attacks on Dole while the vice president could maintain he himself had not done so.

"I don't want to engage in negative campaigning," Bush said.

Meanwhile, Rep. Jack Kemp (R-N.Y.) and former Delaware governor Pierre S. (Pete) du Pont IV jumped into the fray today by trying to show they were above such tactics.

"I think the Bush-Dole debate . . . diminishes their campaigns, diminishes them," Kemp said, holding up a copy of this morning's Des Moines Register, which featured the front-runners' tangle as its lead story.

Kemp, who is fighting to avoid a fourth-place finish here, said Bush and Dole "should be embarrassed" by their feud and warned that voters "are getting turned off" by it.