BY MARC CAPUTO, BETH REINHARD AND GAIL EPSTEIN NIEVES

Mel Martinez closed in on becoming the first Cuban-American U.S. Senator Tuesday night, leading Betty Castor by a razor-thin margin that, with a handful of precincts still to be counted in scattered counties around the state, could trigger an automatic recount and lead to legal challenges.

In the late-night fog of Election Day, Castor's campaign said it was consulting lawyers to consider legal action because it believed Martinez planned a suit. Martinez's camp denied it planned to go to court.

Martinez, the White House's hand-picked man, was so unsure of his Election Day lead that he remained in his Orlando hotel room past midnight today, just 24 hours after wrapping up his campaign in Miami-Dade.

It was there, at a former car dealership early Tuesday, that Martinez stood beneath a banner that summed up his campaign: ``Hagamos historia.''

There's a reason it didn't say ''Let's make history'' in English. The gravity of the phrase would have been lost in translation.

Martinez needed every Hispanic vote, with a lead so narrow that it could be blamed on stealth candidate Dennis Bradley of the Veterans Party, who garnered about 2.3 percent of the vote. Because the margin may be within one-half of 1 percent of the ballots cast, state officials might have to conduct an automatic machine recount. Overseas absentee ballots had yet to be counted.

Castor thanked supporters gathered in a Tampa hotel ballroom at 11 p.m. Martinez stayed cloistered in his hotel room in Orlando, seat of his home county, which he appeared to lose by about 6,000 votes. Castor was leading in her home counties in Tampa Bay.

She, too, was trying to make history. She wanted to be the first Democratic woman to represent Florida in the U.S. Senate and only the second female senator in the state's history.

Martinez's victory would be a devastating blow to the Democratic Party, which now holds only one statewide office in Florida, occupied by Sen. Bill Nelson. Not since Reconstruction have Republicans so dominated the state.

Martinez could thank heavy support from Hispanics, who responded viscerally to his ethnicity, his immigrant success story and his skill at telling it.

The White House helped, too, loaning him advice and advisors from the earliest days of the campaign. Originally, strategists figured Martinez could help Bush. But the president's far stronger showing in the state put the lie to the notion.

All along, Martinez's campaign was far from easy.

The long hours on the campaign trail were more grueling than the former federal housing secretary expected. And, in such a bitter campaign race, the toll on his reputation was almost more than he could bear.

As a bridge-building moderate in Orange County, he was well-liked by the Republican establishment and Democrats alike and seemed like a natural to seek statewide office.

But by campaign's end, he and his family endured commercials suggesting that he was a mean bigot. The ads from Castor, the Democratic Party and an abortion rights group berated him for opposing so-called hate crimes legislation and for his labeling of a Republican primary opponent as a tool of the ``radical homosexual lobby.''

In the final days of the campaign, Castor started spreading stories suggesting Martinez unethically reaped financial benefits while he was housing secretary. Castor was careful to avoid claiming Martinez did anything illegal.

An outraged Martinez went to great lengths to deny the innuendos, saying that he would have never done anything sleazy because ``there are thousands of immigrant children that look to me as a role model.''

Martinez, 58, came to the United States without his parents from Cuba when he was 15 as part of Operation Pedro Pan, a movement spearheaded by the Catholic Church to bring children to the United States from Cuba.

Time and again, he used the story to equate communism with terrorism. In doing so, he suggested Castor didn't have the same stomach to fight terrorists.

Martinez's case in point: former University of South Florida professor Sami al-Arian, who awaits trial on charges that he helped Palestinian suicide bombers. Martinez said Castor, should have taken stronger action against al-Arian when she was campus president in the mid-1990s. Castor countered that if al-Arian were such an obvious threat, he should not have been permitted to campaign with George W. Bush in 2000 and visit the White House.

Martinez had hopscotched the state Monday and played second fiddle to GOP heavyweights Jeb Bush and Rudy Giuliani. Only in Miami-Dade was Martinez introduced as the headliner at an event. Martinez appeared to have won more votes in the county than Bush.

On his six-city tour, Martinez was so at ease Monday that he fell hard asleep in his chartered DC-9's plush leather chairs that accommodated his large frame.

Later, he walked around the cabin handing out Halloween treat leftovers to reporters, saying, ``I'm trying to sweeten you up.''

Martinez's staffers were confident of victory because they thought they had run a superior campaign -- at least on television, which is a must in a state as big as Florida.

Martinez kept the plan simple: He first introduced himself to voters as an immigrant kid who grew up to become federal housing secretary. He soon ran pointed and successful negative ads bashing his opponent, interspersing those commercials with new spots calling for ''rock-solid'' Social Security and hurricane relief.

Castor, who spent a good two weeks responding to Martinez's attacks, was slow to seize the initiative in her ad campaign. She jumped from topic to topic -- prescription drugs, Martinez's aggressive campaign style, her healthcare initiatives, her support for embryonic stem-cell research and the need to raise the hourly wage of minimum-wage workers.

Also, while Martinez embraced the Bush brand, Castor seemed to avoid being identified with John Kerry for months.

Castor got some needed help from the Democratic Party and the abortion-rights group Emily's List. Both ran similar ads calling Martinez mean, especially for what they suggested were gay-bashing positions that Martinez took in the Republican primary campaign.