The norm since World War II is for presidents to score their highest job approval ratings in their first term, then slump dramatically in their second. From Harry Truman immediately after World War II to George W. Bush in the opening years of the 21st century, this has been the trend in the Gallup poll, the long-running chronicler of presidential job approval ratings: In numerical terms, the 11 presidents from Truman to Bush II entered office with an average job approval rating of 65 percent and left with an average of 48 percent.

If Obama wants a model of how to finish strong, it’s Bill Clinton. After a choppy first term that saw Democrats lose control of both houses of Congress in 1994, Clinton rebounded strongly to post approval scores well above 50 percent throughout much of his second term. A prosperous economy helped. So, it appeared, did Republican overreach in pushing for his impeachment as an outgrowth of the Monica Lewinsky affair.

Who knows—the economy could take off again, boosting Obama along with it. The Republicans could overreach on some matter of major import. Or a sudden “rally around the president” event, such as (God forbid) a major terrorist attack, could propel the president’s approval rating dramatically upward.