Obama in statistical dead heat with Mitt Romney, Rick Perry, Ron Paul and Michele Bachmann

President Obama is statistically tied with each of four named Republican presidential candidates in the latest Gallup poll asking which candidate voters would choose if the election were held today. Among independent voters, the only candidate Mr. Obama beats is Minnesota Rep. Michele Bachmann.

Former Massachusetts Governor Mitt Romney's suport was strongest, garnering 48 percent compared with Mr. Obama's 46 percent of registered voters asked.

Rick Perry, who announced his candidacy less than two weeks ago, tied Mr. Obama with 47 percent each.

Among registered voters, the president scored higher than Bachmann and Rep. Ron Paul, though both of those differences were still within the margin of error for the poll conducted August 17-18. Against Paul's 45 percent, Mr. Obama took 47 percent and compared to Bachmann's 44 percent, Mr. Obama garnered 48 percent.

Among independents, who are widely seen as the deciding factor in the actual election, Mr. Obama fared slightly worse. Romney garned 47 percent to Mr. Obama's 44 percent, while Perry took 46 percent to Mr. Obama's 44 percent.

Paul took 46 percent of independents versus Mr. Obama's 43 percent. Bachmann was the only candidate to lose among independents to Mr. Obama, who took 48 percent against the Minnesota Republican's 42 percent.

CBSNews.com special report: Election 2012

"Gallup research shows that these types of election measures at this stage in the campaign are not highly stable, and one can expect changes in the relative positioning of Obama and various GOP candidates in the months ahead," the polling organization said.

"With the first official votes for the Republican nomination more than five months away, and with the very real possibility that GOP candidates such as Sarah Palin, Rudy Giuliani, and George Pataki may jump into the race, much could still change as the election process unfolds," Gallup added, noting that Texas Governor George W. Bush led Vice President Al Gore 55 percent to 41 percent in August 1999. Gore garnered a slightly higher national popular vote total than Bush in the 2000 election.

The poll, conducted by telephone, of 1,026 adults, including 879 registered voters, has a margin of error of plus or minus four percentage points.