SAN DIEGO -- If there were any doubts about his support for comprehensive immigration reform, Sen. John McCain appeared determined to erase them Monday when he spoke in front of about 2,000 Latinos gathered at the National Council of La Raza's annual conference.

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The presumptive Republican presidential nominee told the enthusiastic crowd that he had not backed away from supporting legislation to legalize millions of undocumented immigrants, as his Democratic opponent, Sen. Barack Obama, has contended.

"I do ask for your trust when I say, I remain committed to fair, practical and comprehensive immigration reform," McCain said. "I mean it. I think I have earned that trust."

The National Council of La Raza is one of the country's largest Latino civil rights organizations. Several North County activists protested outside the convention, calling the organization racist for its efforts to legalize undocumented immigrants.

In recent years, North County communities have been on the front line of the immigration debate. Escondido, for example, generated national attention for its failed effort to create an ordinance banning landlords from renting to illegal immigrants.

On Sunday, also speaking at the convention, Obama repeated recent criticisms that McCain had retreated from supporting an immigration reform bill he helped write with U.S. Sen. Ted Kennedy, D-Mass.

On Monday, McCain fired back, saying that Obama was absent from bipartisan negotiations to draft the measure.

McCain's bid for the GOP presidential nomination was nearly derailed by his co-authorship of the failed Secure Borders, Economic Opportunity and Immigration Reform Act of 2007, which would have created a path to citizenship for the nation's estimated 12 million illegal immigrants, a position anathema to many Republicans.

During the primaries earlier this year, McCain shifted his stance, saying that he would not support his own bill. He said that the country needed to secure its borders first before he would support immigration reform that included legalizing undocumented immigrants.

"We can't let immigrants break our laws with impunity," McCain said during his speech. "We can't leave our borders undefended. But these are God's children … and we cannot forget the humanity that God commands us as we seek to remedy this problem."

The Arizona senator received cheers and applause from the audience throughout the half-hour speech at the downtown convention center. McCain touched on economic issues most, saying that he would keep taxes low to help small-business owners and that he would double child deductions from $3,500 to $7,000 to help families.

Oceanside City Councilman Rocky Chavez, a McCain supporter, said afterward he was pleased with the senator's speech because he demonstrated knowledge of Latino concerns, such as immigration, education and trade.

"I think the selling point is he knows Mexico, he knows Central America," Chavez said. "I don't think Obama's ever been to Mexico."

In recent weeks, Obama and McCain have heavily courted the Latino vote by making speeches at high-profile gatherings, such as the League of United Latin American Citizens conference earlier this month.

The campaigns are appealing to the up to 10 million Latinos expected to vote in the Nov. 4 election. Many of those voters live in key swing states such as Nevada, New Mexico, Colorado and Florida.

McCain acknowledged that he has an uphill battle to earn Latino votes, many of whom are Democrats. Several recent polls suggest that he is trailing Obama by double-digit margins among Latino voters, some of whom have been alienated by tough rhetoric against illegal immigrants among some GOP candidates.

"I know many of you are Democrats, regrettably, and many of you would usually vote for the presidential candidate of that party," McCain said. "I know I must work hard to win your votes, but you have always given me a respectful hearing, and I appreciate it."

After his speech, McCain took several questions from the audience. The senator, dressed in a dark suit and red tie, did not deviate from his scripted speech except when two antiwar demonstrators briefly interrupted the event.

"The one thing Americans want us to do is to stop yelling at each other," he told the crowd, drawing some laughter.

Speakers called on McCain to end immigration raids on families and to do more to stop the deaths of immigrants entering into the country on foot through the deserts.

McCain decried the deaths as a "failure of the federal government to exercise its responsibilities."

The senator also appeared frustrated by a question on whether he would make immigration reform a top priority if he is elected president.

"Of course, it's my top priority," McCain said. "It will be my top priority. Otherwise, I would have not done what I did. I think my actions speak for themselves."

Pamela Vargas, a 22-year-old college student from San Francisco, said McCain's speech did not go far enough because he did not mention support for a bill that would help illegal immigrant students earn legal status, called the Dream Act.

Vargas was one of several students who attended the conference to hear what McCain had to say on the bill. One of the members of her group was able to ask McCain a question about the measure.

"It was weird because he didn't address the Dream Act until he was asked," Vargas said. "It's not his priority."

However, McCain got high marks from some who heard the speech.

Calvin One Deer, a program director at Palomar College, said he was impressed with the passion that McCain demonstrated. After hearing both Obama and McCain at the conference, One Deer said, he remained undecided, but said McCain gave the better speech.

"I came here with low expectations, and I'm leaving thinking, 'He really had passion,'" One Deer said. "Out of the two speeches, I think I would give McCain the edge."

The Associated Press contributed to this story.

Contact staff writer Edward Sifuentes at (760) 740-3511 or esifuentes@nctimes.com.