ATLANTA -- A new InsiderAdvantage/Poll Position survey shows that Sen. John McCain has moved out to an 18 point lead in Georgia over Sen. Barack Obama in the presidential race.

The poll released Wednesday shows 56 percent of likely registered Georgia voters prefer McCain to 38 percent for Obama. Two percent prefer other candidates and four percent are undecided.

The poll of 506 registered likely voters, weighted for age, race, and gender, was conducted Wednesday evening. It has a margin of error of +/- 4 percent.

The steep decline for the Obama campaign likely explains why the candidate is moving resources out of Georgia and into other states, according to InsiderAdvantage’s Matt Towery.

"This is a huge slide from what had been, in our prior surveys, a relatively close race," said Towery. "The reason is simple—Obama lost serious ground in virtually every demographic."

“At first glance it would seem that Obama is headed for no better than the low 40 percentile level achieved by John Kerry in 2004," Towery added. "But let me warn observers that in both our national tracking and surveys in other states, the biggest change has been a near parity between the two candidates among the youngest of voters."

“Should that group return to Obama and the African-American vote end up where we expect it to be, the race could be closer in November. But as of now Georgia is no longer a “leans McCain” state. As of this survey, Georgia is in the McCain column.”

The poll, to remain consistent with seven total state polls conducted around the nation by the firm Wednesday evening, does not list Bob Barr as a candidate.

“Having Bob Barr’s name on the ballot would likely take a net point or two from McCain, but at least at this stage, Barr’s presence is not an essential piece of the electoral pie in Georgia,” Towery said. “If the race tightens, that could change.”