ES MOINES - With the first vote of the 2000 presidential campaign fast approaching, a pair of confident sounding front-runners, Republican George W. Bush and Democrat Al Gore, raced across Iowa yesterday and urged supporters not to be complacent. But the boldest prediction about tomorrow's caucuses came from Democratic challenger Bill Bradley, who said he was ''going to surprise a lot of people.''
A poll to be published today in the Des Moines Register showed that the race has changed little in the last two weeks, with Gore holding a 2-to-1 lead over Bradley, and Bush leading his closest challenger, publisher Steve Forbes, by more than 2-to-1.
But, as is often the case with the Iowa caucuses, the final days were dominated by an effort by some campaigns to beat expectations and tighten the races.
The outcome of the Republican caucuses could depend largely on the size of the turnout among social conservatives, while the Democratic race could turn on whether enough voters are convinced Bradley is healthy enough - politically and physically - to be a strong Democratic candidate.
Bradley has said several newly publicized bouts of an irregular heartbeat were not worthy of attention, and he attributed them to a switch from Gatorade to caffeinated cream soda.
Late last night, Bradley campaign trumpeted an endorsement from the Des Moines Register, which said Bradley's ''vision is compelling.'' and that ''there is a fundamental decency about him.'' The paper also endorsed Bush, saying '' We judge him to be a leader with good and decent instincts.''
The former NBA star, who trailed Gore 56 percent to 28 percent in the Des Moines Register poll, was hoping for nearly 40 percent of the vote, which his campaign believed would be interpreted as a victory. Traditionally, candidates who do better than expected here are often viewed as victors even if they don't win.
One of the biggest question marks yesterday was the strength of Republican social conservatives. If history is a guide, a last-minute move by these voters, who are among the most fervent opponents of abortion, could determine whether one of Bush's challengers makes a strong finish.
But unlike in some prior years, the Christian Coalition has been divided and the social conservatives have seemed split. As a result, all of the Republican candidates yesterday tried to rally this group to their cause.
Bush again responded to questions about his stand on abortion. While the Texas governor has said throughout the campaign that he is opposed to abortion, he has said he wouldn't insist on an antiabortion litmus test for judicial nominations or a vice president. Yesterday, Bush said he believes the Republican Party should keep a platform plank that calls for banning all abortions.
''It's going to be up to the Congress if America is ever ready for a constitutional amendment,'' Bush said. ''I understand that. I think the thing that's important for our party is to nominate somebody that can lead the country, somebody who can lead us toward a better understanding of life, and somebody who can find common ground on issues such as partial-birth abortion and parental notification.''
While publicly expressing concern about the turnout, Bush privately has expressed confidence that he will win both in Iowa and in New Hampshire the following week.
At a gathering of supporters at the Sioux City Hilton yesterday, Bush declared: ''The state of Iowa is the first step in ending the Clinton era.'' Supporters, surrounded by handmade Bush signs - ''Iowa loves Bush'' and ''Bush for Sioux City'' - cheered.
Forbes, who four years ago fizzled in Iowa after focusing mostly on his flat tax proposal, yesterday continued his focus on abortion and other social issues. He had a scary experience in Mason City, where his plane had to make three landing attempts in dense fog.
''The weather couldn't stop us, and the political establishment is not going to stop us, and we are going to show the world what that means Monday night,'' Forbes told 300 people in Clear Lake.
Gary Bauer, the former Reagan adviser, and Alan Keyes, the talk-show host, also both drew sizable crowds as they hop-scotched across the state.
At a windswept cemeteryin Des Moines, Bauer held a news conference at the grave of a stillborn fetus, which was found by workers at a wastewater-treatment plant several years ago.
Although the baby was stillborn and not aborted, Bauer said the fetus represents a ''coarsening of our culture.''
Asked whether it was appropriate to hold a photo opportunity at the cemetery, Bauer said, ''I think symbolism is important for this particular day,'' referring to the 27th anniversary of the Roe v. Wade Supreme Court decision that established abortion rights.
Senator Orrin Hatch of Utah, at the bottom of most polls, continued his low-budget campaign, which could end soon depending on his showing here.
Though Iowa polls sometimes are poor indicators of a caucus vote, the Des Moines Register poll was filled with good news for Bush. It showed the Texas governor with 43 percent, followed by Forbes at 20 percent, Keyes and Arizona Senator John McCain with 8 percent, Bauer with 6 percent, and Hatch with 1 percent. The remaining voters were uncommitted or not sure.
Bush, speaking in Grinnell, said he has ''a good chance, but people should not be complacent. That's why I'm working so hard right now, to make sure people hear the call.''
The fear of complacency, shared by all of the campaigns, is justified. Unlike an all-day primary, the caucus is held at night and often takes three hours, a procedure that is likely to attract between 10 percent to 25 percent of the state's 1.8 million registered voters, and relatively few of the independents that Bradley, in particular, needs for a strong showing.
But whatever happens in Iowa, both Bush and Gore had very different scenarios awaiting them in New Hampshire.
Bush is facing his toughest challenge there from McCain. A Concord Monitor poll released yesterday said that 35 percent of those surveyed backed McCain, while 32 percent favored Bush, while a Newsweek magazine poll showed Bush leading 40 percent to 31 percent.
The Democratic race in New Hampshire was even closer, with 45 percent backing Gore and 44 percent favoring Bradley, according to the Monitor. Gore led in the Newsweek poll at 50 percent to 41 percent. All of the figures have a 6 percentage point margin of error.
Gore traversed the eastern half of Iowa yesterday on a final, frenetic campaign swing before the caucuses. Confident with his double-digit lead in the polls, Gore pleaded with Iowa supporters to brave what has been bitterly cold weather and make it to the caucus meetings.
He also took a subtle shot at Bradley, whom the Gore campaign has accused of trying to lower expectations of its own performance to make a Gore victory look less meaningful.
''What are the expectations if Senator Bradley scored a victory?'' Gore asked Democrats at Fort Dodge's Iowa Central Community College.
''My expectation, in the event that occurred, would be that he would do exactly what he has said he would do, and take as his model for leadership style ... he says the one he admires most is Ronald Reagan's,'' because Reagan liked to focus on a few issues, Gore said.
''Well, I understand that. There's something to be said for it. But I disagree with it,'' because Reagan ignored the federal deficit and other crises, Gore told the cheering crowd.
In Cedar Falls, Massachusetts Senator Edward M. Kennedy appeared with Gore and picked up on the idea of expectations. Kennedy, who ran unsuccessfully for president in 1980, said the Bradley campaign has been saying that 30 percent in the Iowa caucuses would be a win of sorts. But ''I remember in 1980, I got 31 percent'' of the Iowa vote ''and I don't remember making a victory speech,'' Kennedy said, drawing laughter and cheers.
For his part, Bradley says he has been sensing a connection with his listeners by reading their eyes.
''The thing I live on are the eyes,'' Bradley told reporters yesterday during an appearance at Clinton Community College. ''And the eyes were there today. I think we're going to surprise a lot of people.''
Bradley has been vigorous and upbeat in the final days of the campaign, despite reports about his episodes of irregular heartbeats and talk that his campaign has lost momentum.
Yesterday, for instance, he was greeted by groups of loudly cheering college volunteers, and even an 8 a.m. breakfast audience mustered the energy to spell out his name cheerleader-style.
Globe Staff writers Yvonne Abraham, traveling with McCain; Michael Crowley, traveling with Bradley; Anne E. Kornblut, traveling with Bush; Susan Milligan, traveling with Gore; and Jill Zuckman contributed to this report. Material from the wire services also was included.
