LOS ANGELES (KNX 1070 NEWSRADIO)  -- Barack Obama has managed to pile up a double digit lead over John McCain, according to an LA Times/ Bloomberg Poll. Respondents split 49% to 37% for Obama in a head-to-head match.

Obama's 12 point lead only grows when pollsters throw independent candidate Ralph Nader and Libertarian Bob Bar into the mix. On a four man ballot voter's support grows for Obama, 48% to 33%, giving him a 15 point spread over McCain.

The base of Obama's success in this poll appears to come from his relative strength against McCain on domestic issues. Democratic and independent voters both say that Obama would do a better job handling the economy, which ranks as the public's top concern. McCain does better on national security issues.

The vast majority of Hillary Clinton supporters have filed behind Obama. McCain only manages to siphon off 11% of Clinton supporters. He also fails to energize his base. Only 58% of voters who describe themselves as conservatives say they'll vote for McCain and 15% of them plan to cross party lines to support Obama. In contrast, 79% of self describe liberals say they will vote for Obama.

Obama and McCain split the white vote evenly with bot candidates getting 39%, fatally wounding the argument that an African-American would not do well among white voters in a general election.

McCain also faces the challenge of President Bush's historically low approval numbers. Public approval for Bush's job performance hit a low for the LA Times/Bloomberg poll. Only 23% of respondent say he's doing a good job.