The Democratic party and Barack Obama's campaign today announced a plan to spend $20m to organise and mobilise Hispanic voters.

Meanwhile, in Washington today buzz grew about Virginia governor Tim Kaine's place near the top of the short list of Obama vice-presidential choices. Kaine, an early Obama backer, could help Obama carry Virginia, and would bring outsider appeal to the ticket. He appeared in Washington today, ostensibly to visit his daughter, and told reporters: "I think I'm just not going to talk about my conversations with the campaign."

The Democrats will focus the $20m on four swing states in the west and south-west with large Hispanic populations. The party aims to take advantage of what it considers a blunder by Republicans who have embraced hard-line immigration policies that have alienated Hispanic voters and provoked them to political action. Democrats say that never before has a national party pledged this much money this early in such a broad programme.

Democrats say Colorado, Nevada, New Mexico and Florida are in play for Obama after voting for George Bush twice. Victories there would reduce pressure on Obama to win Ohio and Pennsylvania, typically the site of brutal fall battles.

At a press conference at Democratic National Committee headquarters this morning, four Hispanic congressmen said Obama's message of "change" on the economy, energy, healthcare, the war in Iraq, immigration and other issues appeals to Hispanic voters. The news conference did not focus on immigration, though polls show it is a top concern for Hispanic voters.

"The reality is that [McCain] is proposing the same initiatives as President Bush, on the war, on social security, the economy," Arizona representative Raul Grijalva said in Spanish, for the benefit of the Spanish-language media present, "and those were a failure for our community, a tremendous damage. For me, the need for our community to choose Barack Obama is economic, political and social".

The money, which comes both from party coffers and Obama campaign funds, will be spent to contact, register and mobilise Hispanic voters, on online organising, media advertising, travel for campaign speakers and staffing in swing states. Democrats familiar with the initiative said the funds will be spent in all 50 states, but focused largely on the Hispanic-heavy swing states.

Obama is poised to carry a majority of Hispanic voters. According to a survey release last week by the Pew Hispanic Centre, a non-partisan research organisation, Hispanic registered voters favour the Illinois senator 66% to 23% for McCain. But by aiming aggressively at the segment, especially new voters, the Democrats hope to increase turnout that will add to his vote total in November, and force McCain to spend time and money campaigning in states that Bush won.

Bush, former governor of heavily Hispanic Texas, made strong inroads with Hispanic voters. His strategists recognised that the group's share of the electorate is growing, and Bush in 2000 and 2004 spent heavily on Spanish-language advertising and enlisted Bush's part-Mexican nephew in the effort. As a result, the Republican party doubled its share of the Hispanic vote in 2004 from 1996, winning 40% to the Democrats' 59%.

McCain, who also hails from a heavily Hispanic state, Arizona, was poised to share in Bush's appeal. In 2006 he was a staunch supporter of ambitious but ultimately unsuccessful immigration reform legislation backed by Bush and leading Democrats. Beginning in 2007 and through the Republican primary, McCain yielded to anti-immigration forces in the party base, however.

"He's got two key problems," said Democratic party spokesman Luis Miranda. "One, he's promising the same failed policies of the Bush administration, and two, he walked on an issue of such importance to the community, like immigration reform, which showed the community that, can you really trust him?"

Colorado senator Ken Salazar said immigration "is not one of the defining issues of our time" but noted that Obama "has not wavered in his commitment" to reforming the system. Obama has long backed a guest-worker programme for low-paying jobs typically filled by illegal aliens, a path to legal status for illegal aliens, and other provisions

Indeed, the McCain campaign has acknowledged the Republican party's poor standing among Hispanics, but the side plans to remind Hispanics of McCain's longstanding ties to the community. The campaign hopes Hispanics won't punish him for their distaste for Republican immigration policies.

In a statement released by the McCain campaign, Florida representative Lincoln Diaz-Balart said: "Unlike Barack Obama, John McCain doesn't need an introduction to the Hispanic community. John McCain has been working for more than two decades for the values, principles and issues Latinos care about."

During the long primary campaign, Hispanics backed New York senator Hillary Clinton nearly two to one, in part because Hispanic voters had a favourable view of former president Bill Clinton, and because of historic cool relations between blacks and Hispanics.

Representative Jose Serrano of New York, a staunch Clinton backer during the primary season, today said Latino support for her transfers to Obama, her fierce rival.

"That love that the Latino community had for Hillary is also a love for change," he said. "It's a love for the future of our country… it's a love for ending those policies which are unfair and it's a love for true change in America."