When John F. Kennedy ran for president in 1960 and for years afterward, political analysts disagreed on whether his Roman Catholicism helped him more in northern industrial states than it hurt him in the rest of the country.

What his victory did was eliminate Catholicism as an issue, although neither party nominated a Catholic over the next generation.

A similar debate is taking place this year over Hillary Rodham Clinton and, if she becomes the first major party female nominee, whether her sex will help or hurt.

Her recent activities and comments make clear she believes it will help. Her campaign this week called women “a critical voting bloc that will help propel Hillary to victory in November 2008.”

Independent evidence agrees her sex is a strong asset in seeking the Democratic nomination. And while it would be premature to say for sure that it will help in the general election, initial signs are that it will be a plus, something a prominent Texas Republican pollster says his party has failed to recognize.

“Republicans underestimate the very powerful symbolism and feel-good emotions that would accompany electing the first woman president,” said David Hill of Houston, director of Hill Research Consultants. “It’s a big deal.”

In a recent column in The Hill, a Capitol Hill-based paper, Hill chided Republicans eager to face Clinton who label her a political version of the late hotel executive Leona Helmsley, known as the “Queen of Mean.”

“Before this is over, Hillary’s candidacy will have more in common with Amelia Earhart’s first trans-Atlantic flight or Sally K. Ride’s first trip into space than Helmsley’s heartlessness,” he wrote.

Andrew Kohut of the independent Pew Research Center for the People and the Press, said a study of 40 statewide elections showed female Democrats did better against male Republicans, largely because they did better among women and no worse among men.

Though conceding that some find Clinton “more polarizing” than some other female candidates, Kohut suggested she would enjoy a similar advantage. He said the Pew study showed “the gender differences in support for Clinton at this early stage in the campaign are, on average, typical for Democratic women who run for statewide office.”

Her advantage is most obvious in polls of prospective Democratic primary and caucus voters. The latest USA Today/Gallup poll shows she attracts 55 percent of women, compared with 44 percent of men. By contrast, Sen. Barack Obama gets 23 percent of women and 20 percent of men.

A similar pattern is evident in individual state polls.

In Iowa, which holds the first caucuses, the latest Des Moines Register poll showed Clinton with a 13-point lead among women, easily offsetting a small lead for Sen. John Edwards and Obama among men.

Some 54 percent of the Democratic turnout in 2004 was female.

Clinton’s campaign has increased its emphasis on her sex with the theme of Women Changing America. Events included last week’s appearance on the television show “The View” and an expanded family leave plan.

She has not shied away from the subject. “If you want a winner who knows how to take them (the ‘right-wing machine’) on, I’m your girl,” she told an AFL-CIO forum.

Still, questions remain. In a University of Iowa poll last spring, 51 percent of likely Democratic caucus goers said Clinton’s gender “will be a problem for her.” Others say she still has a polarizing image.

But a similar advantage appears in general election surveys. A recent ABC News-Washington Post poll showed her leading Rudy Giuliani by 8 points overall but by 18 points among women.

GOP candidates and the Republican National Committee already are attacking many Clinton statements and proposals. But Kohut agreed that if women perceive she is being attacked as a woman, “there could be a rallying to her.”

Hill said the GOP needs to find ways to counter her candidacy. One way: Pick a woman as its vice presidential nominee. “That might be enough of a symbolic benefit for independents and ticket-splitters worried whether they can afford another Clinton presidency,” he wrote.

Recent polls show an overwhelming proportion of Americans say they could vote for a woman as president, and a majority said the country was ready to do so. But the ultimate success or failure of the Clinton candidacy will tell us more than any hypothetical poll.

Carl P. Leubsdorf is Washington bureau chief of The Dallas Morning News. His e-mail address is: [email protected].