Jon Terbush June 9, 2011, 6:45 AM

As it stands now, the biggest threat to President Obama’s reelection bid isn’t a Republican challenger — it’s the economy, stupid.

Obama’s overall approval rating — and by extension his odds of winning reelection next year — are inextricably tied to the health of the economy, as a number of recent polls have made very clear. While it’s still a long way till election day, at the same time that economic pessimism has grown polls are showing Americans losing confidence in Obama’s ability to turn things around.

The good news for Obama is that polls have not yet shown any of the Republican presidential candidates consistently topping him in hypothetical matchups, or even putting up much of a fight. So while these polls have reinforced the time-tested notion that the economy’s health is crucial to a president’s reelection bid, they’ve also illuminated how weak the current crop of Republican frontrunners are — including presumed frontrunner Mitt Romney.

Obama got a sizeable boost from the killing of Osama bin Laden in early May , with polls pegging his approval rating as high as a 60% in the aftermath. But that support has evaporated over the past month, with some polls now showing Obama’s approval rating breaking even, or even falling back into negative territory. A CNN poll released Wednesday found that 48% of Americans approved of the president’s job performance, the same percentage who disapproved. In addition, a widely-cited ABC News/Washington Post poll released Tuesday showed a negative 47% to 49% split; one day later, a PPP poll gave Obama a similarly bleak 46% to 48% split.

The driving cause of that drop off has been Americans’ increasingly pessimistic views of the sputtering economic recovery, and their mounting fears of a double-dip recession.

In that ABC News/ WaPo survey, nearly six in ten respondents said they didn’t think the economy had even begun to turn around yet. In addition, 48% of respondents in the CNN survey said they feared another great depression was on the way, up from 41% one year ago. And as Pew reported this week, the percentage of Americans who say they are hearing mostly bad news about the economy spiked to 46% this month, its highest level since March 2009 — in other words, the highest level since shortly after Obama’s inauguration.

Meanwhile, Obama’s approval rating for his handling of the economy is deep underwater. That ABC News/WaPo poll also found voters giving Obama his worst marks ever on the economy, with 40% of Americans giving him a thumbs up, and 59% giving him a thumbs down. The current TPM Poll Average shows that 40.9% of Americans approve of Obama’s economic management, while 56.9% disapprove — and its showing little sign of improving.

The downward trend there is striking:

[Editor’s note: The numbers cited in this article may differ from those depicted in the graph below as more data is entered. ]

The dire economic picture should be disheartening news to the Obama reelection campaign. However, it would be much more worrisome if those dismal indicators correlated to poor showings in theoretical contests with possible Republican challengers. Though a number of GOPers have very high national profiles, none have yet matched up well in head to head contests with the president.

This is particularly the case for Mitt Romney, the presumed frontrunner for the GOP nod and the candidate who has typically polled strongest against Obama. Despite touting his experience as a businessman, Romney hasn’t made deep inroads against Obama to date. He currently trails Obama 47.5% to 42.6% in the latest TPM Poll average, and the trend line shows him sinking.

Saddled by “Romneycare,” in a Republican party primary where the base loathes the federal health-care law it partly inspired, Romney looks weak. Further, there are lingering questions about whether Romney’s Mormon faith will drive GOP primary voters away. A Quinnipiac poll released Wednesday found that just 60% of voters would be comfortable with a Mormon in the White House, while over a third (36%) said they’d be “somewhat” or “entirely” uncomfortable with that. That same Quinnipiac poll showed Obama beating Romney 47% to 41%, and all other comers handily.

According to the latest TPM Poll Average, only 35.5% of Americans have a favorable impression of Romney, while 39.2% have an unfavorable opinion of the former Massachusetts governor.

If the economy doesn’t turn around, there will be ample room for a Republican to swoop in and peel voters away from Obama. But right now, even with the economy in the tank,

2012, 2012 elections, Barack Obama, CNN, Economy, Mitt Romney, Pew, Polls, Pres '12