While Republicans hog the headlines with their presidential straw vote here Saturday, Vice President Gore is quietly assembling an Iowa campaign machine that key Democrats think could hand him a victory in next winter's delegate caucuses, which count for much more.

Gore and his rival Bill Bradley also tried to steal a little of the spotlight on Iowa this week, spending several days campaigning here. The vice president started slowly in Iowa and elsewhere this year, and now faces a stiff challenge from Bradley, who has been intensively organizing in this state for months. But in recent weeks, Democrats here say, Gore's operation has shown noticeable improvement. Gore and Bradley both campaigned in Iowa this week.

"Bradley's done a nice job and they're working hard, but the vice president is leaps and bounds ahead of what he was two months ago," said Iowa Democratic Chairman Rob Tully. "He's not taking anything for granted, which acknowledges that Bradley could give him a serious race here. But he's going forward with a real campaign. He's out organizing."

Iowa Gov. Tom Vilsack, officially neutral even though his wife, Christie, is active in the Gore campaign, agrees. "Gore is much better organized than he was two months ago," Vilsack said. "The last two trips have been very good. He's more relaxed, mixing with the crowds and answering questions."

Vilsack, like many other Democratic governors interviewed at the recent assembly of state executives in St. Louis, said he does not worry about polls showing Gore trailing Texas Gov. George W. Bush (R) in a general election trial heat. "Once it gets down to two candidates and you focus on the issues, it will be like my race," said the freshman governor, who came from behind to defeat a favored Republican last November.

Much the same message came from Roy Barnes, the new governor of Georgia, who has endorsed Gore for the Democratic nomination. "Vilsack and I were both behind three weeks out" from Election Day, Barnes said. "Because of mass media, people focus very late on the election choice, and when they do, Democrats are on the right side of the issues they care about."

Bradley spokesman Eric Hauser said the former New Jersey senator's campaign operation in Iowa is right on schedule and described the stepped-up activity by the vice president as a reaction to the quick start Bradley made here and elsewhere.

"If they're putting more effort into organizing it's probably at least in response to the early momentum we were generating," Hauser said today. "At some level we have an advantage in that Bradley can move around more easily and be more informal about it, which helps get people connected."

With Iowa awash with GOP presidential candidates and the media this week, both Bradley and Gore decided to join the party. Gore spent two days on a bus tour through parts of the state and Bradley wrapped up three days of campaigning in the state this afternoon. Hauser said Bradley would be back next week for his 14th visit of the year.

Hauser said the Bradley campaign has moved into a new phase, from introducing the candidate to Iowa activists to the first stage of intensive organizing for next winter's precinct caucuses. "We're tracking well with how we've wanted to do things, building the base, getting the field organization," Hauser said.

But the institutional advantages that accrue to a sitting vice president have helped Gore make up ground. He has received the endorsements of the biggest public employees union here, the American Federation of State, County and Municipal Employees, as well as the Iowa chapter of the United Auto Workers.

But Tully said Gore has also stepped up efforts to reach out to rank-and-file Democrats. "He's not leaving any of that for granted," Tully said. "One of the things I'm noticing is that the vice president appropriately is gearing a lot of his campaign to smaller groups similar to Bradley's. Quite frankly he's extremely effective in that campaign style."

In Boone on Thursday afternoon, Gore asked grandparents and veterans in the crowd of some 125 people to raise their hands and said he felt a special bond with them, as a Vietnam vet and a new grandfather. After finishing his stump speech, he asked everyone to stay around for a personal word.

Bradley did the same kind of personal campaigning the previous evening, talking to about one-third as many people on the porch of a Victorian home near downtown Des Moines. While Gore was accompanied by Iowa Attorney General Tom Miller, a longtime Democratic incumbent, Bradley's host, former state representative Jack Hatch, has a reputation as a maverick. Many of the guests said they had worked for liberal presidential candidates such as House Minority Leader Richard A. Gephardt (D-Mo.), who won the Iowa caucuses in 1988, and 1972 Democratic nominee George S. McGovern.

In states with that kind of reputation, such as Vermont, Bradley appears to pose his greatest challenge to Gore. Vermont Gov. Howard Dean, who briefly considered running against Gore himself, said he was staying neutral because "we have two very good candidates and I see no need to get in the middle." Bradley has a stronger organization in Vermont than Gore, Dean said.

But he was the exception among the Democratic governors in St. Louis. California Gov. Gray Davis, a strong Gore supporter, said, "I think Al Gore will win the primary decisively and the general election." Noting criticism that Gore suffers from a personality deficit, Davis said, "I was the least charismatic of four candidates running for governor last year, but experience and being right on the issues are what win in California."