For years, President Barack Obama’s personal favorability ratings served as a political firewall that sustained him through an economic recession, grueling fights with congressional Republicans, and the grind of a re-election campaign.

But after a rough start to Obama’s second term, Americans increasingly view the president unfavorably. And perhaps most concerning for the White House: an Associated Press analysis of public polling shows it has become more difficult over time for Obama to fully rebound from dents in his favorability ratings.

“It’s a slow cumulative effect,” Republican pollster David Winston said, adding that personal favorability “is a much harder number to move if it starts to go south.”

The public’s increasingly negative view of Obama may be less of a concern for his future given that he is barred from running for re-election. But the president still needs a strong connection with the public in order to rally Americans around his policy proposals and, in turn, to show Congress he remains politically relevant at a time when lame duck status is lurking.

The president’s advisers need only look at Obama’s predecessor, George W. Bush, to see the impact of a crumbling relationship with the public. Positive impressions of the Republican trailed off in the beginning of 2005 amid public frustration with the Iraq war and the government’s flawed response to Hurricane Katrina. Bush’s favorability rating never recovered and he struggled to fulfill significant policy goals throughout the rest of his presidency.

A series of recent polls show Obama’s personal favorability now leaning negative, including an NBC News/Wall Street Journal Poll released last week that found positive views of Obama at the lowest point of his presidency and down 6 points from earlier in October. The drop follows the 16-day government shutdown, the cascade of problems during his health care law’s rollout, and another flood of revelations about U.S. government spying.

White House officials blame the shutdown in particular for Obama’s falling favorability, given that it resulted in shuttering many federal services and furloughs for hundreds of thousands of Americans, while again highlighting the troubled ties between the president and Capitol Hill. But Obama aides note that the impact of the shutdown on congressional Republicans has been even worse, with both their personal and job performance ratings at record lows.

“Everybody gets hurt when there’s dysfunction in Washington,” White House spokesman Jay Carney said.

Throughout Obama’s presidency, his job approval and personal favorability ratings have generally risen and fallen in tandem. But his favorability numbers, which often reflect the public’s gut-level reaction to a politician, generally remained the more positive of the two measures.

That, the president’s supporters argue, made the public more likely to give him a chance even when they disagreed with his policies or the direction the country was headed. His strong likability was seen as a particular asset during his 2012 re-election campaign when most polls showed that voters saw him in a more favorable light than his Republican rival Mitt Romney.

“For the president, it’s meant that people have cared about what he had to say because they liked him,” said Celinda Lake, a Democratic pollster.

The question for the White House now is whether that dynamic will hold if the public’s personal opinions of the president continue to sour. An Associated Press-GfK poll from early October found that 52 percent of Americans didn’t think Obama was very honest and were split on whether he was even likable.

The president’s favorability has taken hits during other points in his presidency. Most polling found the public’s impression soured in late summer 2011 around the first round of debt ceiling negotiations and again last summer in the midst of his presidential campaign.

Although Obama’s favorability improved somewhat after each hit, he never fully recovered, with each rating rebound peaking below earlier average favorability ratings.

For example, Obama began 2011 with majority favorable ratings in most polling. When the debt ceiling fight pushed his favorability below 50 percent in late 2011, he came back to an average right around 50 rather than above it. This latest battle has led to average ratings in the mid-40s, worse than he’s seen at any point previously.

Past presidents have also struggled to recover from dips in their favorability ratings.

Bush left office with majorities saying they had both a negative impression of him personally and disapproved of his job performance. And former President Bill Clinton’s favorability numbers never recovered after a fall in 1998 as the Monica Lewinsky story unfolded, though his job approval remained strong through his last days at the White House.

Republican President Ronald Reagan evoked the warmest reaction from the American public, leaving office with high job approval numbers, 63 percent according to Gallup polling in December 1988, and a majority holding a favorable impression of him personally.

(AP)