President Barack Obama has forged a complicated personal connection with the American public: Many voters consider him a principled and inspiring leader even as they question his policies and job performance. That delicate bond has given Obama a reservoir of goodwill that is sustaining his presidency in tough times – a political firewall of sorts. As Jessica Luna, a 21-year-old Democrat from Austin, Minnesota, puts it: “If you like someone, you'll give them time to accomplish their goals.” But Obama's likability ratings have slipped a bit, raising an ominous question: Is the bond fraying? History suggests such a connection could give way at any time – over almost any issue – and send Obama into the kind of nosedive from which other presidents never recovered. Obama needs to look no further than his predecessor. George W. Bush enjoyed high approval ratings through much of his first term, only to see them slip during the Iraq war and then plummet after the botched response to Hurricane Katrina. His presidency limped to a conclusion. “There was a sense that this man didn't care,” says Republican pollster Steve Lombardo. “That can be virtually debilitating.” Every president has character traits that bind him to voters, at least initially. That gut-level connection matters to people as much, and arguably more, than a president's policies, sometimes keeping him afloat through political storms. Obama's personal approval rating has trended 5 to 7 percentage points higher than his job approval rating, a likability benefit that is not inconsistent with past presidents. Bill Clinton's strongest attribute was empathy. The sense that he would work for you, to use one of his phrases, “until the last dog dies,” kept his presidency going after its rocky first two years and during the Monica Lewinsky intern scandal. Bush was seen as a strong and decisive leader, traits that kept many voters on his side despite misgivings over the Iraq war. He knew that character trumped policies when he declared in 2004, “Even when you might not agree with me, you know where I stand.” Obama's advisers like to draw parallels between their boss and another Republican president, Ronald Reagan. His likability ratings remained high despite an economic recession in the early 1980s and rough patches later. “People believed that he had strong principles,” says senior Obama adviser David Axelrod. “They thought he was a likable, admirable person.” Axelrod says Obama is viewed the same way – and there is evidence that he is right. At least, to a point. Obama's job approval rating, perhaps the best gauge of an incumbent's reelection chances, has been hovering around 50 percent since October. It would probably be much lower – the health care debate and bank bailouts have drained him politically – if voters did not like him so much, Democratic and Republican pollsters agree. “Voters think Obama is sincere, wants to do well and has a stable and real marriage,” Republican pollster Bill McInturff said. “Those are all important things because when people like a president, they will give him a chance to do his job even when they're not so sure about his policies.” A look inside Obama's ratings show that he has actually gained ground since taking office on the public's view of his values and his ability to manage a crisis, according to NBC News-Wall Street Journal polling conducted by McInturff. But those are not the character traits that got him elected. He has experienced double-digit declines on personal attributes that hew closely to the Obama political brand – his ability to inspire, unify the country and achieve his goals. While those ratings are still high, the trend could spell trouble. But like Bush and Reagan before him, Obama's strongest suit may be voters' belief in the sincerity of his motives. Item: Nearly 6 in 10 Americans say Obama is more interested in serving the public than interest groups, according to a CBS News/New York Times poll. Only 13 percent think the same of Congress. Still, strategists in both parties say the health care fight for Obama could be the rough equivalent of what the first years of the Iraq war were for Bush – a long, but less-than-debilitating slog that weakened his bond with the public. What could destroy Obama's bond, as Katrina did for Bush? Anything that galvanizes the public's growing questions about his abilities to inspire and unify the US. Or anything that raises questions about the purity of his motives. Deal-cutting on health care. A failure to create promised jobs – or an incident that shows a lack of empathy toward people who have lost them. Anything could go wrong. But, clearly, the character issue has bought Obama time. “If he's able to turn things around, he'll stand up as one of the top presidents in history,” says Republican voter Tony Gay of Redwood City, California, who worries about the direction Obama has pointed the country. The Republican called Obama “honest, sincere – more of a people's president.” The question is, how long will that be enough?