Bradley, meanwhile, campaigned among New Hampshire business leaders and, in a newspaper interview, offered new criticism on the old question of whether Gore was guilty of race-baiting in his 1988 campaign.

The day's rat-a-tat fueled an increasingly noisy and negative contest for the Democratic presidential nomination and its first two rounds of voting in Iowa, on Jan. 24, and in New Hampshire, on Feb. 1.

His motorcade stirring a storm of dust, Gore ventured down dirt roads to a farm house outside Sioux City to meet with 150 farmers and show off his know-how on the complexities of hog packing and commodity pricing.

"You don't have to have a Ph.D. in farm economy to understand this," Gore said in an apparent swipe at Bradley, the Princeton basketball star and Oxford scholar.

Gore left the more direct criticism to Etsch, helpfully spelling his name so reporters in the back of the barn could be sure to get the man's indictment of his former senator.

Etsch described Bradley as ignorant of agricultural policy and unresponsive to the New Jersey farmers he represented for three Senate terms. "I would call him up and everything else," Etsch said. "I heard nothing."

Gore, whose campaign paid for Etsch to fly here from his Monroe Township home, promised to "raise Cain until we fix this farm economy."

Sen. Tom Harkin also stood beside Gore in the freezing-cold barn and assailed Bradley's record on farm policy. The senator, especially popular among Democrats in Iowa's farming communities, also stars in a new Gore TV ad meant to underscore that Bradley voted against an amendment that included aid for farmers hit by 1993 floods.

Bradley, who trails Gore in Iowa polls by 20 points or more, has conceded he started the presidential race knowing little about farm policy, but he says he's learned plenty in 31 visits to Iowa this past year.

In an interview Thursday with The Associated Press, Bradley said the farmers' downturn came during the Clinton-Gore watch and he tossed a long-distance question back at Gore: "Where were you? Where were you when this was all happening?"

Separately, in a published discussion with The Boston Herald, Bradley said Gore had introduced the issue of escaped murderer Willie Horton in the 1988 Democratic primary campaign against Massachusetts Gov. Michael Dukakis.

Horton, a black man who committed rape while on furlough, became a symbol of racially divisive campaigning during the Dukakis-Bush general election race later that year.

"Gore introduced him into the lexicon," Bradley said. "It bothers me a great deal. ... I wouldn't have used Willie Horton."

Gore could have found other examples if he wanted to show that Dukakis was soft on crime, Bradley said. "The racial dimension to that -- there were probably a lot of other people who fit into that category."

The Gore campaign, which is bringing Dukakis to Iowa next week to campaign for Gore, immediately put reporters in contact with the former Massachusetts governor and marshaled a denunciation from House Minority Leader Dick Gephardt.

"It's unfair to attack Gore in this way because it just isn't true," Dukakis told the AP in a telephone interview from California.

When Gore questioned him about the prison furlough program during a 1988 debate, Gore did not name Willie Horton and "there certainly was no suggestion on the racial side," Dukakis said.

"There weren't any pictures of Willie Horton as there was in the Bush attack ads" that aired during the general election fight with then-Vice President George Bush, he said.

Susan Estrich, campaign manager for Dukakis in 1988, said it didn't matter whether Gore used Horton's name because "he had become the symbol of the furlough problem well in advance" of that April 1988 debate.

"In political terms, it's fair to say the Willie Horton issue was the furlough issue and the furlough issue was the Willie Horton issue. And, it had such racial overtones and was so divisive, frankly we were surprised when he raised it in the debate," Estrich said Thursday evening.

In a statement that Gore aides handed out as the vice president campaigned later Thursday in Nashua, N.H., Gephardt said Bradley's statement "unfairly smears" Gore.