PHOENIX (By Dan Nowicki, Arizona Republic) July 10, 2008 ― John McCain is in aggressive pursuit of Hispanic voters but is struggling to overcome a negative Republican brand and a crucial political pivot on immigration reform that he made during the GOP primaries.

The increasingly influential Hispanic voters could determine whether McCain or Democratic rival Barack Obama carries presidential swing states such as Florida, Colorado, New Mexico and Nevada. The bloc even could make an impact in reliably Republican states such as Arizona and Texas.

McCain, the Republicans' 2008 presumptive White House nominee and once a staunch champion of comprehensive immigration reform, will speak Monday at the annual conference of the National Council of La Raza, one of the nation's largest Hispanic civil-rights organizations.

Obama is expected to address the group Sunday.

For McCain, the stop comes amid a series of aggressive overtures toward Hispanics marked by Spanish-language ads and international visits to Colombia and Mexico.

McCain's campaign hopes the senator from Arizona can make national inroads with Hispanics despite the harder lines against illegal immigration taken by many of his fellow Republicans.

So far, however, polls show Obama has a large lead over McCain among Hispanics. Gallup pollsters put it at 59 percent for Obama to 29 percent for McCain in June, with a margin of error of plus or minus 3 percentage points.

McCain allies cast Obama, a first-term senator from Illinois, as still relatively unknown to the Hispanic community. They are counting on picking up support as Hispanics take a closer look at Obama and his policies toward small businesses and Latin American trade.

McCain hopes Hispanics will remember and reward the years he spent fighting for comprehensive immigration reform.

Obama and the Democrats are trying to complicate McCain's image. They are highlighting McCain's primary season position shift that found him expressing support for border security before other reforms, such as a temporary-worker program and a pathway to citizenship for illegal immigrants already in the country.

McCain called it a lesson learned from the public outcry that killed his 2007 Senate legislation. During one debate, McCain went as far as saying he wouldn't vote for the bipartisan immigration bill he co-authored.

"Now, I know Senator McCain used to buck his party on immigration by fighting for comprehensive reform, and I admired him for it," Obama said. "But when he was running for his party's nomination, he abandoned his courageous stance and said he wouldn't even support his own legislation if it came up for a vote."

McCain supporters praise McCain as a leader on the immigration issue while accusing Obama of trying to exaggerate his own role in the debate.

"Senator Obama was consistently and absolutely AWOL, nowhere to be seen in any of the meetings that we held on this issue of immigration," said Rep. Lincoln Diaz-Balart, R-Fla., during a conference call organized by the McCain campaign. "It's absurd for him now to take credit on that issue when he was nowhere to be seen. He was an absolute non-player."