WASHINGTON - US President Barack Obama retains a big lead over possible Republican rivals in the 2012 election despite anxiety about the economy and the country's future, according to a Reuters/Ipsos poll on Wednesday.Obama's approval rating inched up 1 percentage point from May to 50 percent but the number of Americans who believe the country is on the wrong track also rose as pricier gasoline, persistently high unemployment and a weak housing market chipped away at public confidence.Obama leads all potential Republican challengers by double-digit margins. He is ahead of his closest Republican rival, former Massachusetts governor Mitt Romney, by 13 percentage points -- 51 percent to 38 percent."Obama's position has gotten a little stronger over the last couple of months as the public mood has evened out, and as an incumbent he has some big advantages over his rivals," Ipsos pollster Cliff Young said."Until Republicans go through a primary season and select a nominee, they are going to be at a disadvantage in the head-to-head matchups in name recognition."Sarah Palin, the 2008 vice presidential nominee, and Romney lead the pack of Republicans battling for the right to challenge Obama in the November 2012 election.Palin, who has not said whether she will run, had the support of 22 percent of the Republicans surveyed and Romney had 20 percent.Representative Ron Paul, a libertarian Republican from Texas, and former pizza executive Herman Cain were tied for third with 7 percent each.The Republican candidates are just starting to engage in their slow-starting nomination race. Young said Palin and Romney had a clear advantage at this stage over other challengers in name recognition among voters.Sixty percent of those polled said the country is on the wrong track, with 35 percent saying it is going in the right direction.The survey was taken after weak jobs and housing reports last week showed the economy is recovering much slower than expected. Unemployment rose slightly to 9.1 percent for the month.The poll, conducted Friday through Monday, surveyed 1,132 adults nationwide by telephone, including 948 registered voters. The margin of error is 3 percentage points.