PHILADELPHIA - At a recent John McCain town hall meeting in Bucks County, Pa., a woman began her question to the Republican presidential candidate with a complaint: "Why, as an American, do I have to push a button to speak English?"

The crowd roared. "I think you struck a nerve," McCain said.

"I tell you, I really get ticked," the woman continued. "You go into Lowe's and it says, 'Entrada.'"

In response, McCain said that he favors comprehensive immigration changes, but only after the borders are secured. The crowd cheered at the latter but quieted when he went on to advocate a "temporary worker program" and the need to accommodate the estimated 12 million people already in the country illegally.

It was a delicate rhetorical dance, illustrating how the issue of immigration pulls McCain in two directions at once.

He was the architect of a failed Senate proposal that would have provided a path to citizenship for illegal immigrants, a policy that an angry conservative GOP base termed "amnesty." To placate them, McCain began stressing enforcement first.

Yet that new emphasis risks alienating Latino voters, who could be pivotal in several closely contested states this fall.

During the past three weeks, McCain has been tangling over immigration with presumptive Democratic nominee Barack Obama in separate appearances before major Latino civil rights groups. The struggle itself is a sign of the Hispanic vote's growing power.

In an appearance last Sunday before the National Council of La Raza in San Diego, Obama said that McCain had "abandoned his courageous stand" on immigration in order to win the GOP nomination, and he promised he would be "a president who won't walk away from something important ... just because it becomes politically unpopular."

Obama said he wants to bring illegal immigrants "out of the shadows" and on the path to citizenship.

Speaking to the same group a day later, McCain said he was still committed to revising immigration laws, noting he had risked "political suicide" by working with liberal Democrats on the legislation.

"Doing my duty to my country is its own reward, but I do ask for your trust that when I say I remain committed to fair, practical and comprehensive immigration reform, I mean it," he said.

Despite the bickering and some rhetorical differences, the two candidates are not all that far apart on the substance of such changes. Obama has voted for the border fence, for instance, and both men want to crack down on employers who hire illegal immigrants.

Vying for Latino votes

Immigration has faded behind concerns over the economy and the Iraq war in national polls, but it remains a hot-button issue in some regions and among some voters, including Latinos.

Obama's campaign hopes for a surge in Latino turnout, while McCain wants to capitalize on recent Republican inroads with Hispanic voters -- and his own ties to the community as a senator from border-state Arizona -- to hold down the Democrat's margin.

McCain makes sure to include in his standard spiel on the issue expressions of compassion for illegal immigrants, whom he calls "God's children" seeking a better life.

"There's a great thing about America, and that is that we welcome all cultures from all over the world," McCain said during the recent town meeting in Pipersville, Pa. "We are the great, great nation that brings people together from all different backgrounds and languages and cultures. And we love the Hispanic heritage. We love the Irish heritage."

The audience of about 1,200 at Worth & Co., a manufacturer of heating and cooling systems, stayed largely silent. In the next breath, McCain added that he thinks immigrants should learn English. The crowd applauded.