Obama's approval rating hits lowest at 40%

Obama's job approval rating dropped to 40% during the week spanning August 8-14, the lowest weekly average of his administration.

During this period, Obama's three-day rolling average also hit a new low of 39% for August 11-13, the first such average below 40% since he took office, though it recovered to 41% for August 12-14, Gallup said in a statement.

"With the exception of a dramatic national or international event, it is usually difficult to pinpoint the causes for the short-term ups and downs in a president's job ratings. In the current situation, it is reasonable to assume that several events of the last few weeks have played a part in depressing the public's approval of Obama," Gallup said.

It said 10 incumbent presidents have sought re-election since World War II, and none has won a second term with final pre-election job approval ratings below 48%.

The last two presidents who lost their re-election bids -- George W Bush and Jimmy Carter -- had job approval ratings in the 30% range in the fall of the election year.

"Thus, Obama's challenge is not only to move his rating back above 40%, but also to push it close to or above 50%," it said, adding that the crucial period for Obama will begin after Labor Day, given the relative quiet on the political front that should be the case before then.

Obama yesterday began a three-day bus tour through Minnesota, Iowa and Illinois.