PHOENIX (By Julia Preston, NYTimes) February 5, 2008 — Spurred by the widespread crackdown on undocumented immigration and by the contentious tone of the national immigration debate, Hispanics are gearing up for Tuesday’s voting with an eye toward making Hispanics a decisive voting bloc nationwide in November.

After decades of relatively low Hispanic electoral participation, last year more than a million legal Hispanic immigrants applied to become citizens, with many saying they had done so to be able to vote. Since then, newly naturalized Hispanic-Americans and citizens since birth have turned out at voter registration fairs and political discussion groups, and pressed relatives to register.

Last week’s primary in Florida, the first state with a big Hispanic population to vote, gave a demonstration of their potential clout. Hispanic voters, who were 12 percent of those voting — a strong turnout for a primary — handed the decisive edge in the Republican contest to Senator John McCain of Arizona over Mitt Romney, the former governor of Massachusetts, according to exit polls by Edison/Mitofsky.

The two candidates were essentially even among white voters, with 33 percent for Mr. McCain and 34 percent for Mr. Romney. But Hispanic voters, including Cuban-Americans and others, favored Mr. McCain by 54 percent to 14 percent for Mr. Romney.

On the Democratic side, Hispanics also contributed to the 16-point victory in Florida of Senator Hillary Rodham Clinton of New York over Senator Barack Obama of Illinois, with 59 percent of Hispanics voting for her and 30 percent voting for him.

Hispanics regard voting this year as a strategy of self-defense, said Sergio Bendixen, a pollster based in Miami. For many of them, Mr. Bendixen said, “the immigration debate has not been about immigration policy; it has been about whether Hispanics belong in America.”

Hispanics “feel they need to vote to show they are a group that cannot be abused or discriminated against,” said Mr. Bendixen, who surveys Hispanics for the Clinton campaign.

On Tuesday, 24 states that include nearly 60 percent of the nation’s Hispanic electorate will be voting in primaries or caucuses. Voting that day will be 7 of the 10 states with the highest percentages of Hispanics among their voters, including New Mexico, where Hispanics constitute more than one-third of the electorate (Democrats will caucus there); California, where they are about 23 percent; and Arizona, where they are about 17 percent.

The electoral energy has been channeled by a voter registration campaign that has built new links between local Hispanic organizations and major Spanish-language media, led by Univision, the national television network.

Both Republican and Democratic strategists say that strong immigration enforcement and tough talk against undocumented immigration by the Republican candidates, with the exception of Mr. McCain, have antagonized Hispanics in general.

“The hard-line rhetoric on immigration is turning off all Hispanics,” said Lionel Sosa, a Republican advertising executive in San Antonio who handled Hispanic outreach in the presidential campaigns of Ronald Reagan and both President Bushes. “When people talk about building a wall and sending those Mexicans back, it comes off as anti-Hispanic. We say: ‘You’re talking about my family, and I don’t like it.’ ”

One newly energized and mobilized Hispanic voter is Silvia Benitez, 45, who was born in Mexico but has been living in Arizona for more than a decade. A community outreach worker in a federal preschool program in Phoenix, Mrs. Benitez sat on the sidelines in the elections of 2004 and 2006 as a legal immigrant.

This election, she said, will be different. Among several recent immigration measures Arizona adopted were the nation’s toughest sanctions against employers who hire unauthorized workers, which took effect Jan. 1.

“We don’t feel safe as a community,” Mrs. Benitez said. “Some people judge you now because of how you appear, your skin color, your English accent.”

Frustrated by President Bush, in her estimation, had failed to push through a bill to give undocumented immigrants a path to become legal, Mrs. Benitez applied for citizenship last year and took her oath as an American in October.

With her measured voice and folded hands, Mrs. Benitez does not look like a firebrand. But she is talking like one. “It is about time for us to take action and make a big movement of political change for Hispanics,” she said.

Another Phoenix resident, Silvia Trinidad, 20, is among a fast-growing group of young Hispanics who have recently reached the voting age of 18. A legal Mexican immigrant since she was a child, Ms. Trinidad is studying criminal justice in college and working for the county sheriff as a detention officer, hoping to become a police officer. She signed up last fall to become a citizen.

“Every vote counts,” Ms. Trinidad said, “and I will be able to vote against the laws they are trying to make now against the immigrants.”

Ricardo Tavizón, 29, a recently naturalized citizen who sells used cars in South Phoenix, said he wanted to vote to challenge immigration enforcement and to represent other immigrants who are not citizens.

Eliseo Medina, executive vice president of the Service Employees International Union, said he was surprised by the response to the voter registration campaign, called Ya Es Hora, Ve y Vota or “Now is the time, go and vote.” .

“In 42 years of organizing, I’ve never seen this level of interest in an election,” said Mr. Medina, whose union is part of the drive.

After helping hundreds of thousands of legal immigrants apply for citizenship last year, the campaign now aims to persuade six million unregistered Hispanics to sign up to vote by November, he said. An estimated 18.2 million Hispanics are eligible to vote.

That goal is plausible, Hispanic leaders said, because of the coordination between community groups, and the newspapers of ImpreMedia, which include El Diario La Prensa of New York, and Univision. The television network is running five public service advertisements about the registration drive, while the newspapers print guides to voter registration. The campaign includes major groups like the National Association of Hispanic Elected and Appointed Officials Educational Fund, a bipartisan organization, and the National Council of La Raza.

Hispanic voters may cast deciding votes again on Tuesday. Nationwide, Senator Obama has pulled to a tie with Senator Clinton, at 41 percent each, according to a CBS News poll released Sunday. In Arizona, Mr. Obama is ahead among Hispanics, by 53 percent to 37 percent for Mrs. Clinton, according to a poll by Mason-Dixon for McClatchy/MSNBC. But in California, where Hispanics make up nearly one-fourth of Democratic voters, Mrs. Clinton has a lead of 52 percent to 20 percent for Mr. Obama, a Field poll conducted from Jan. 25 to Feb. 1 found.

Mrs. Clinton and Mr. Obama support giving legal status to undocumented immigrants. But she has far stronger name recognition among Hispanic voters, polls show.

In the Republican races, Mr. McCain holds a wide margin of support among Hispanics over Mr. Romney, who promised tougher action against undocumented immigrants. But Mr. McCain may pay for his Hispanic support by losing ground with conservatives. On Monday, Roy Beck, the president of NumbersUSA, one of the biggest groups battling undocumented immigration, sent out an e-mail alert that he said went to 1.5 million supporters, urging them to vote against Mr. McCain.

Based on recent trends, a surge in Hispanic voter registration would strongly favor the Democratic Party in November, since 57 percent of registered Hispanics identify themselves as Democrats while 23 percent align with the Republicans, according to a study in December by the Pew Hispanic Center, a Washington research group. While immigration is a litmus-test issue for many Hispanics, it is not their only concern. Polls show that the war in Iraq, the economy and education are also on their minds.

With the voter registration drive just starting, its full force will not be felt until November. But Hispanic leaders’ goals are clear.

“It is not inconceivable,” said Cesar Conde, executive vice-president of Univision, “that Hispanics will have the key role in electing the next president of the United States.”