WASHINGTON (Reuters) - Democrat Barack Obama and Republican John McCain courted Hispanic support on Saturday, and Obama accused his White House rival of backing away from comprehensive U.S. immigration reform under pressure from his party.
In separate appearances before a group of Latino public officials, the two presidential contenders portrayed themselves as dedicated champions for Hispanics -- a fast-growing and critical swing voting bloc in November's election.
Obama took aim at McCain's approach to comprehensive immigration reform and his change of emphasis on legislation to offer a pathway to citizenship for the country's 12 million illegal immigrants.
McCain, an Arizona senator, broke with his party and worked for the plan, which ultimately failed in Congress amid heavy Republican opposition.
But he shifted his approach during the fight for the party's nomination to emphasize the need to secure U.S. borders before addressing the status of illegal immigrants.
"One place where Senator McCain used to offer change was on immigration. He was a champion of comprehensive reform, and I admired him for it," Obama, an Illinois senator who supported the proposal, told the National Association of Latino Elected and Appointed Officials.
"But when he was running for his party's nomination, he walked away from that commitment. He said he wouldn't even support his own legislation if it came up for a vote," he said. "If we are going to solve the challenges we face, we can't vacillate, we can't shift depending on our politics."
McCain, who appeared before the group ahead of Obama, admitted the plan "wasn't very popular with some in my party" but said he would still work for a broad-based overhaul of U.S. immigration laws.
"It'll be my top priority yesterday, today and tomorrow," McCain said when asked if immigration reform would be high on his to-do list in his first 100 days in office.
A McCain spokesman accused Obama of voting for "poison pill" amendments that doomed the immigration deal.
"It was Obama himself who worked to kill the Senate's bipartisan immigration reform compromise last year," Brian Rogers said in a statement.
The Obama campaign shot back that McCain had thanked Obama for his support on the issue in 2006.
McCain told the Latino officials the proposal failed because Americans were not confident Congress would protect U.S. borders before dealing with the question of illegal immigration.
"I want to assure you we will address this issue in a humane and compassionate fashion," he said, calling illegal immigrants "God's children."
Hispanics are the fastest growing minority group in the United States and account for about 9 percent of the national electorate. They could be a critical swing voting bloc in November battleground states like Florida and in the U.S. Southwest.
In 2004, President George W. Bush won about 40 percent of the Hispanic vote -- a Republican record -- in defeating Democrat John Kerry. But opinion polls show Republicans have been hurt with Hispanics by the debate over immigration reform.
Obama has had his own problem with Hispanics, who heavily supported his primary rival Sen. Hillary Clinton of New York.
Polls show Obama has rebounded among Hispanics since clinching the Democratic nomination. Many polls show McCain falling short of Bush's 40 percent of Hispanic support.
Obama, who will be the first black nominee of a major U.S. political party, stressed the groundbreaking nature of his candidacy to the Hispanic group.
"I'm hoping that somewhere out in this audience sits the person who will become the first Latino nominee of a major party," he said.
McCain was interrupted four times during his speech and subsequent questions by protesters who challenged his staunch backing of the Iraq war. Officials of the Hispanic group apologized and said they were not members.
Obama, who has called for a withdrawal of U.S. combat troops from Iraq within 16 months of taking office, said Hispanics had borne a heavy burden during the war.
Both candidates stressed economic and education proposals they said would help Hispanics. McCain touted his plans to cut corporate tax rates and make Bush's income tax cuts permanent, along with his support for free trade proposals.
"It is a terrible mistake to raise taxes during an economic downturn," McCain said. "I reject the false virtues of economic isolationism. Any confident, competent government should embrace competition -- it makes us stronger."
Both McCain and Obama will speak next month to another influential Hispanic group, the National Council of La Raza, at its convention in San Diego.