If the presidential race was held today, according to the latest Gallup poll, Barack Obama would be … in a lot of trouble. In head-to-head battles with the top four Republican candidates in the race at the moment, Obama can’t score 50% against any of them — and is in virtual ties with all:

President Barack Obama is closely matched against each of four possible Republican opponents when registered voters are asked whom they would support if the 2012 presidential election were held today. Mitt Romney leads Obama by two percentage points, 48% to 46%, Rick Perry and Obama are tied at 47%, and Obama edges out Ron Paul and Michele Bachmann by two and four points, respectively.

These prospective election ballots — measured Aug. 17-18, well over a year before the Nov. 6, 2012, election — indicate that the race for president at this point is generally competitive, with voters fairly evenly divided in their preference for giving Obama a second term or electing a Republican candidate. Even though the four Republican candidates tested have varying degrees of name recognition, they all fare roughly the same.

Gallup’s analysis focuses on Obama’s low approval ratings and their impact on his numbers:

President Obama’s job approval rating is hovering around the 40% mark. This is below the rating that any of the six incumbent presidents re-elected since Eisenhower has had at the time of the presidential election. However, in August of the year before they were re-elected, Ronald Reagan (43%) and Bill Clinton (46%) were both below 50%. Obama’s position of rough parity against leading GOP candidates shows that more Americans at the moment say they would vote for Obama than approve of the job he is doing — perhaps a reflection of the continuing lack of a strong front-runner on the Republican side.

It’s more a reflection of an early stage in the process of choosing a challenger.  The numbers for each are remarkably similar, which indicates that this poll reflects Obama more than the individual Republican candidates.  All of Obama’s figures fall into a three-number range (46-48), while his challengers fall within a five-number range (44-48), all within the margin of error for the poll.

Given that, the breakdown of party affiliation is perhaps even more interesting.  Obama draws between 84-86% of Democrats and loses between 10-12% regardless of opponent.  He narrowly loses independents against all challengers except Bachmann, where he wins 48/42.  Ron Paul has the least grip on Republican voters, holding 82% with 11% going to Obama, followed by Bachmann at 86/9.  Perry actually edges Romney 92/6 to 91/6 respectively, which is really just a statistical tie.

Republicans appear ready to rally around Romney or Perry, and independents appear equally comfortable with either.  Voters know Romney well, so his numbers probably won’t change much except in relation to Obama’s, while Perry still has to introduce himself to a large number of voters.  That gives him more potential upside and downside, but he’s clearly off to a strong start, and the attacks over the last week don’t seem to have done much damage at all.