Hang onto your hats. It may be a long, bumpy ride.

"You may think I'm crazy, but the odds are now better than 50-50 that the Democrats won't know who their nominee is going to be until their convention," said Robert Strauss, former chairman of the Democratic National Committee, in an interview late yesterday.

"We could very well not have a nominee until the third ballot in New Orleans," said Eddie Mahe Jr., former executive director of the Republican National Committee.

With the first two rounds of the presidential marathon over, the early message from the voters is clear: Don't know yet.

Neither of Iowa's winners repeated in New Hampshire. None of the winners either week in either party attracted much beyond a third of the vote. No candidate has yet to win an "away" game, on inhospitable turf, in a state much beyond a border away from his birthplace. Each party's preacher has done well: They're the only candidates stirring passion on the stump, and their best days are still ahead.

What it amounts is an extraordinary -- and, for a time, self-perpetuating -- muddle. The confusion in each party's race heightens the ambiguity in the other, for the news media and the public have only so much attention to pay.

Last week, Rep. Richard A. Gephardt (D-Mo.) was robbed of the media wave he had hoped to ride out of Iowa after his victory, because Pat Robertson's second-place GOP "surprise" and Vice President Bush's "collapse" stole the headlines and the network news shows.

This week, it is unclear how much Gov. Michael S. Dukakis (D) will get from winning next door to his home state of Massachusetts, in part because the Bush "comeback" is the more riveting tale.

But how can a vice president "come back" in a race he was leading by 20 percentage points only last week? It's another anomaly of the season. Most television networks along with this newspaper conduct nightly "tracking polls" now. The political junkies in all the campaigns -- and within the attentive public -- "knew" Bush to be a goner on Saturday, breathing on Sunday, surging on Monday. In 1988, expectations are measured against last night, not last week.

And with no broad issues seeming to be at stake in either party's primaries, voter preferences are volatile night to night. In the absence of large themes, the presidential primaries have come to resemble Senate or gubernatorial races, full of cut and thrust about each candidate's character. Negative advertising -- long considered unpresidential -- is now the coin of the realm and seems to change votes. Gephardt was the target of Sen. Paul Simon's (D-Ill.) commercials suggesting he is untrustworthy because he had changed his mind on many issues. Bush's commercials in the final 72 hours depicted Sen. Robert J. Dole (R-Kan.) as "Senator Straddle."

Dole is plainly bitter. On NBC-TV last night when anchorman Tom Brokaw asked whether he had any message for Bush, who was on camera at the same time, Dole said: "Stop lying about my record." Aides in both camps expect plenty of vitriol in the weeks ahead.

The negativism of the season has kept any of the candidates from breaking onto a larger stage. "We're seeing more crashes than liftoffs out of Iowa and New Hampshire," said Democratic pollster Geoffrey Garin. And the failure of any candidate to seize control of either party has given the back-runners in both an incentive to resist the pressures of debt, disappointment and fatigue -- and fight on. What started out as a 13-man field at the beginning of this month may only be pruned down to nine- or 10-man field through "Super Tuesday," March 8. "You stay in it, you wind up with 50 or 100 delegates, and you might have a seat at the table," Mahe said.

Over the years, Iowa and New Hampshire preserved their place at the start of the nomination calendar in part because they spare the rest of the electorate the overload of large-candidate fields. That's how it worked in the past. But this year, said Democratic media consultant Frank Greer, "The winnowing process is not winnowing very fast."

One reason is surely the mirror-image economies of the two opening-round states. Iowa farm land has lost nearly 60 percent of its value in the 1980s, making it fertile sod for Gephardt's message of anticorporate populism and economic nationalism and for Dole's urgent call for fiscal austerity and budget freezes. Neither message traveled especially well into New Hampshire, where the unemployment rate hovers around 2 percent.

Two cool, pragmatic, steady-as-she-goes Yankees -- Dukakis and Bush -- played better in the Granite State. "You are dealing with a very ambivalent electorate that can't decide where they want the country to go," Mahe said, "so they're saying, 'I better vote for the guy from next door. He won't burn down my house.' "

Now, the two New Hampshire winners face their share of perils in the weeks ahead.

Dukakis has been a "hidden front-runner" since the day former Colorado senator Gary Hart temporarily dropped out of the Democratic race last May. But until last night, he had drawn a kind of bye, with his two principal rivals -- Gephardt and Simon -- training their attacks on each other rather than on him.

Now with a win to his credit, Dukakis is likely to become everyone's target, with the lead attacker likely to be Sen. Albert Gore Jr. (D-Tenn.).

While the other candidates trekked through Iowa and New Hampshire, Gore concentrated on his base in the South, where 14 states will hold primaries or caucusues on March 8 as will six elsewhere. He has husbanded $2 million to $3 million to spend in the region -- not quite as much as Dukakis but more than Gephardt and Simon, both of whom are broke.

Gore will argue that Dukakis is weak on defense and unconvincing in his plan to balance the budget with improved tax collection. Dukakis, anticipating the attack, gave a foreign policy speech last weekend in which he used the word "strength" 38 times.

On paper, Dukakis stands to do well in the non-southern Super Tuesday states -- Massachusetts, Rhode Island, Washington and Maryland -- and has pockets of strength in the two biggest Sunbelt states, Florida and Texas.

Simon, with his third-place finish last night, is $500,000 in debt and faces grave fund-raising problems. His best hope -- a longshot -- is to beat Dukakis in the Minnesota caucus next Tuesday.

Gephardt will focus on the South Dakota primary, also Tuesday. A win there would help him to raise the money to mount a respectable Super Tuesday campaign.

Polling results suggest Gephardt's tough talk on trade will play well in the South, where appeals to economic nationalism are popular. One poll taken in Texas this week, for example, shows he shot up from single digits to 27 percent after his victory in Iowa. Simon's southern prospects are more problematic, but he has a reason to want to hold on to a week after Super Tuesday, where he would be a favorite son in the Illinois primary, March 15.

Jesse L. Jackson will concentrate on the South, using his showing in Iowa and New Hampshire to solidify his base of black voters and to appeal to white voters facing hard times economically.

Former Arizona governor Bruce Babbitt has scheduled a meeting in Washington today with his family and top staff. Many political experts expect he will be the first Democratic casualty of the campaign.

Hart, despite his meager showing last night in a state he carried four years ago, is expected to stay in the race, hoping that the voters will sour on his rivals and turn to him.

On the Republican side, Bush, by pulling out a win, "has avoided three weeks of bashing in the press," said Texas GOP Chairman George Strake, "and that's going to keep him strong for Super Tuesday, where he's got the best organization by far."

Bush has problems in the states before Super Tuesday, though. Dole is favored in the South Dakota primary and the Vermont "beauty contest" on March 1. Robertson forces will be formidable in the Minnesota caucus and the Feb. 28 Maine caucus.

The Bush strategy, according to campaign manager Lee Atwater, is to head straight south. "The next big event is South Carolina," said Atwater, a South Carolinian. That primary is March 5, three days before Super Tuesday.

Both the GOP front-runners' campaigns are well-financed, and neither Bush nor Dole is likely to get out of the race without being dragged out.

"These two men are both in their 60s, and they both know that when this thing is over, he's had his last shot at the brass ring," said a top adviser to one, who asked to not be identified. "They don't like each other very much. They're both incredibly tough. No one is going down easily."

Rep. Jack Kemp's (R-N.Y.) third-place finish in New Hampshire enables him to keep his campaign going, but barely. He has money problems, and there are no states on the horizon in which he is likely to break through as the leading candidate. He'll take a stab at Minnesota next week. The fourth-place finish by former Delaware governor Pierre S. (Pete) du Pont IV probably means the end of his candidacy.

Robertson's failure to get beyond barely breaking into double digits in a state where there are not as many fundamentalist Christians as in Iowa leaves unproven his claim that he can expand beyond his base. But the South is full of fundamentalists, and its GOP primaries typically do not attract many voters. Both conditions, plus plenty of money, bode well for him to continue to the end, perhaps as a spoiler.

Staff writer Maralee Schwartz contributed to this report.